By default Quake II doesn't allow you to change your weapon hotkeys which can be a bit annoying in a heated battle.
I'm gonna show you how to change your weapon keys without having to play keyboard twister or scroll like madman to get to the desired weapon.

1.Go to Quake II\baseq2 folder (xatrix and rogue for the expansions)
2.Create a new text document and rename it autoexec.cfg
3.Inside the cfg file copy/paste the following for the base game, The Reckoning and Ground Zero:

bind 1 "use Super Shotgun"
bind 2 "use Chaingun"
bind 3 "use HyperBlaster"
bind 4 "use Railgun"
bing 5 "use Rocket Launcher"
bind g "use Grenade Launcher"
bind x "use BFG10K"
bind MOUSE3 "use Blaster"
bind MOUSE4 "use power shield"
bind MOUSE5 "use invulnerability"
bind q "use quad damage"
bind e "use environment suit"
bind F5 "echo Quick Saving...; wait; save quick"
bind F8 "echo Quick Loading...; wait; load quick"
bind END "menu_quit"

bind 1 "use Super Shotgun"
bind 2 "use Chaingun"
bind 3 "use ionripper"
bind 4 "use Railgun"
bind 5 "use Phalanx"
bind 6 "use HyperBlaster"
bind g "use Grenade Launcher"
bing h "use Rocket Launcher"
bind x "use BFG10K"
bind z "use trap"
bind MOUSE3 "use Blaster"
bind MOUSE4 "use power shield"
bind MOUSE5 "use invulnerability"
bind q "use quad damage"
bind e "use environment suit"
bind r "use dualfire damage"
bind F5 "echo Quick Saving...; wait; save quick"
bind F8 "echo Quick Loading...; wait; load quick"
bind END "menu_quit"

bind 1 "use Super Shotgun"
bind 2 "use Chaingun"
bind 3 "use Plasma Beam"
bind 4 "use Railgun"
bind 5 "use ETF Rifle"
bind 6 "use HyperBlaster"
bind g "use Grenade Launcher"
bing h "use Rocket Launcher"
bind z "use Tesla"
bind x "use BFG10K"
bind c "use Prox Launcher"
bind MOUSE3 "use Blaster"
bind MOUSE4 "use power shield"
bind MOUSE5 "use invulnerability"
bind q "use quad damage"
bind e "use environment suit"
bind r "use double damage"
bind t "use defender sphere"
bind v "use IR Goggles"
bind F5 "echo Quick Saving...; wait; save quick"
bind F8 "echo Quick Loading...; wait; load quick"
bind END "menu_quit"

If you don't like these bindings you can change them to whatever you want, I did not include the regular Shotgun and SMG because once you get your hands on the Super Shotgun and Chaingun you don't need to use them ever again, I also didn't include the Chainfist because it's completely worthless.

Cant say much for other Quake's - i play mostly Q2. But what the problem? 1-9 is work for base game weapons. And... well, for me i found easy way to scroll weapons - scrolling items. I set to mouse wheel scroll inventory items (weapons as well as you know) forward and backward. Middle mouse button - scroll only weapons (without editing configs it allow only forward scroll). So i have one backward scrolling and two way to forward weapon scrolling.
And 1-9 for most weapons.

To activate item chosen by mouse wheel i use RMB. I think it most useful controls that you can get in ingame menu customization - useful for both weapons and activating items (although im almost never use them, hard with Quad is too easy for me).

That all actually take me second to pick needed weapon. Numbers or wheel, or MMB (3d button).

... You know what... there is really one useful think you suggest here. Change [G] for Grenade launchers instead of grenades. Any others letters is useless - it take more second (at least 1) to remember which one.

Mouse buttons 4-5\etc... How many mouse have that? I dont like such pseudo-gaming chinese mouse. Normal usb-wired 3-buttons mouse. Even Razor and Microsoft Hardware do trash sometimes (Microsoft do trash even for models that not trash initially - happened for headsets an web-cameras, even for top\highest price models, i have good fullhd web from them, but i need replace broken headset - and new pieces of same model have very bad microphone instead of very good one and lack of one of the buttons; as for cameras as i know new same hd and fullhd have bad auto-focus module - mine is perfect). A4Tech, SteelSeries and any else - always be trash.