I'm not all that good myself but this is what I did.

Simple guide for the script:
1) Download the script from www.overcards.com/wiki/moin.cgi/BetPot
2) Download Autohotkey from www.autohotkey.com
3) Unzip and you should have 2 .ahk files, the main Betpot and a second smaller named betpot_default_hotkeys.
4) Open the second betpot_default_hotkeys in ex notepad. Here you will find what the keys do, I use the right mouse button so that would be this line:

~RButton::
Pot(getid(),"1 1 1 1", "smallblind", "ssnl", 0)
return

The 1's are the fraction of the pot you would like to bet, the first if preflop, second flop, third turn and last we have the river. So here we bet the pot as default everytime.

All you hafto do is change these numbers to fit your style. Preflop is set to 4bb raise, so if you use 3.5bb you enter (3.5/4) = 0.875 instead of the first 1. Example:

~RButton::
Pot(getid(),"0.875 0.8 0.66 0.66", "smallblind", "ssnl", 0)
return

Here we bet as default: 3.5bb pre, 4/5pot on flop, 2/3pot on turn and river.

5) Save and load the betpot script.
6) Try it.

Hope that helps.