For Half-Ogre techies, IMO there's really only one background choice: the Rare Half-Ogre Birth helps offset their inherent IN penalty.

Dwarves have a lot more flexibility. The only tech-based background I would stay away from is Magick Allergy: it won't let you pick up anything magical, even to sell them. (Clanless Dwarf is also a waste; you'll quickly be able to find or build a better hammer than the game gives you.)

Good early tech disciplines include Herbology and Explosives. Half-Ogres might eventually consider Smithy, since good large armor is nearly impossible to come by; (Dwarves can always use the lightweight Gnomish chainmail until uncovering the best tech armor late in the game, by following a Dwarven quest to its very end.) Get to at least expert Repair sooner rather than later, since a lot of mid- and late-game encounters are capable of damaging weapons and armor.

Stay away from Perception unless you're planning to use guns; it's a waste otherwise. And remember that firearms aren't nearly as effective as you'd think, especially in the early game. (Also, ham-handed Half-Ogres can only use two-handed rifles, not one-handed guns.) Likewise with Beauty; Charisma, however, increases your potential follower count as well as being a prerequisite for Persuasion.

As a Dwarf, invest early points in Dexterity (for more turns when fighting) and Strength (for more weapon damage). Bear in mind that Dwarves are naturally slower, so you're unlikely to reach a 20 DX and its accompanying speed bonus; any backgrounds that offer a DX bonus (like, say, Troll Offspring or Beat With an Ugly Stick) aren't worth the tradeoff.

Half-Ogres should make use of their Strength bonus; get to 20+ as soon as you can afford to for a huge damage bonus. Also consider getting to 20 DX (with the help of Charged Rings; see below) for a nice speed bonus as well. But these are midgame goals; early on, you'll have other priorities.

When you get to Tarant, a Dwarf could buy a small smoking jacket (+20 to reaction) while a Half-Ogre would have to pickpocket the only large one in the game off of Chukka's back. As a bonus, you'll look the part of a tech-based dandy. Also, get Magnus to build you a balanced sword (and soon after, a featherweight axe); there's a schematic for the awesome Pyrotechnic Axe hidden in the sewers, guarded by a battalion of incredibly tough robo-arachnids.

If you want an electro-cane (or as it's called, a Shocking Staff) you'll need to invest in charges to power it. (Ditto with the Chapeau of Magnetic Inversion, available as a quest item in Black Root.) These can be bought, or made with a small investment in Chemistry. Electrical also gives you Charged Rings, which boost Dexterity and help offset Dwarves' natural slowness. Sebastian could build you Charged Rings (and eventually a Shocking Staff) but if you want a Tesla Rod you'll have to invest your own points into Electrical.

Even with the Rare Birth background, Half-Ogres are limited to a max IN of 18. To reach the top level of any tech college, you'll have to buy some Potions of Intelligence, and use them by a) quaffing one, b) while it's in effect, invest your points in the college of your choice, and c) when ready to manufacture something, quaff another one and build it before the effects wear off.

As you can see, there are a lot more options than points, especially in the early game. Best strategy is to focus on what's necessary. A point in Melee lets you use most weapons. One point in Explosives plus a point in Throwing provides Molotov cocktails. One point in Herbology provides healing salves. Get your DX up to at least nine, to invest a second point into Melee (and possibly Throwing) for greater accuracy and fewer critical misses.

You'll get a point every level, plus an additional point every five levels. That means 64 points by level 50, which will eventually mean you'll have enough to build your character however you like. But it can make for slow going in the early game; tech is definitely a harder road than magic. Good luck.