First of all what you need to understand is that there is absolutely no need to dual class Imoen in BG1. She is by far the best thief option in the game, whose stats you can manage right from the start.

Secondly, you are not correct. If you dual class Imoen when she is level 4 she will not get her thief abilities back until she is level 5 mage. That's going to take you another 20,000 XP points to reach without access to her abilities. The problem with BG1 is that XP does not come quickly like it does in the sequel, and it will feel like she's never going to get there, and you will be forced to take on another thief.

The bottom line is that she is far better used as pure thief, especially since you have adequate mage alternatives.

Maybe I'll hold off dual-classing her for this playthrough then. I like her as my thief, so doing without her thief abilities for awhile is a little daunting.

Thanks for the quick-reply. And let me know if there's anything else you think I should know.

Hickory is right as always. Imoen is best kept as thief in BG1 unless your main character is thief in which case I dualclass her at level 6. But ofcourse you can dualclass her when she is level 4 and she will regain her abilities when she is mage level 5. With the expainsion, 20K experience is not too long as it was. GOG version is with expansion. So if you want an extra mage in your party go ahead and dualclass.

One extra information about the dualclassing is that weapon trainings dont stack. If I remember right, Imoen starts with bows and small swords. If you choose small swords again when you dualclass her as mage, then you practically waste to learn a new weapon. I myself choose slings when she gets mage levels. When she is lv5 mage, she will be able to use swords, bows and slings. Small detail but there it is.

Imoen is the best thief? What about Coran with his 20 dex?

You only really "need" to dual class Imoen if you're playing BGT, but I'll offer you the opposing opinion as someone who found it very useful to dual her. If you're only at level 4 after beating Cloakwood, then there are a huge number of wilderness areas you haven't explored yet. These areas don't really require thieving skills, and they should easily give you enough experience for a few early levels. I dual-classed Imoen at level 6 or 7, started the process before I even got to Cloakwood, and completed the dual classing by the time I got to Baldur's Gate. That should give you some sense of how much experience is available to you in this game in the areas you haven't been to yet. While you're working on leveling her, I would suggest occasionally going Ankheg hunting in the area north of the Friendly Arm Inn, as they give you much more experience than any other wild creatures.

Coran is a Fighter/Thief, meaning his thief stats are watered down, plus you cannot manage his stats from the very start. Overall, Imoen has the best stats of any companion in the entire trilogy.

I see what you mean. Thanks for pointing that out!

If you want to dualclass Imoen switch to illusionist or conjurer, not to pure mage. But there's no need to do so if you have another mage or bard to handle the arcane spells in the party.

Alrighty, so first off, thanks for all the help. You guys are great.

Second, based off what I'm reading from your responses, I've decided not to dual-class Imoen, at least not for this playthrough. I have Dynaheir, so I'm covered with a mage, and Imoen is my thief.

So, since I'm wanting for more XP though, my plan is now enter Baldur's Gate, explore the city a bit, do some quests (both within the city and around the world), and once my party is averaging level 6 or so, go to Ulgoth's Beard for TotSC content.

It's worth noting that this is only possible in the original engine. If you are playing TuTu, Trilogy, or (to my knowledge) the Enhanced Edition, you can't dual class into a specialist mage.

True. I dont know about EE but in Tutu or Trilogy you can only dualclass to normal mage.

I just thought of something I'd like to point out. Dual classing Imoen can be a viable option if you want fewer than six party members and your party doesn't already have a mage. You would also get more XP since the XP you typically get is divided by the number of party members. Although multiclass characters are treated as two (or three if you have that many classes) characters.

This is a pretty advanced style of play so I wouldn't recommend if you are practically new to the game.

If you mean a multi-class character counts as 2 party members when divvying up XP, I'm pretty sure this isn't correct. Their (single) share of XP is just split between their two classes, which is why they level slower than single class characters of the same type.

If you've got a F, T, C, and F/T, then XP will be split 4 ways, and the F/T will tend to have a lower Fighter level than the F, while the F/T will also tend to lag behind the T in Thief level. The F/T gets to use both Fighter AND Thief abilities as the trade off.

It is worth noting the following:

At lower levels, XP requirements typically double at each level. Therefore, multi-class characters will only be one level behind their single-class counterparts.

At higher levels, typically starting in the 9-11 range (depending on class), every level requires the same amount of experience; hence, multi-class characters will only gain levels half as fast. For instance, at 3 million experience, a single class Mage will be level 18 (and hence able to cast 9th level spells), while a double class Mage (like Aerie) will only be level 14 (and hence will have just gained 7th level spells). This causes multi-class characters to be significantly worse than their single-class counterparts at these levels.

At still higher levels, the level gap continues to widen; however, levels stop mattering. After level 20, there isn't much to gain for being a higher level, except for HLAs, which multi-class characters acquire as quickly as single-class characters. In the meantime, multi-class characters get to catch up (although it is worth noting that triple class characters never get 9th level spells unless you use a mod to raise the XP cap (normally 8 million in ToB) to 9 million or higher).