You would still need to set cheat-check off if you plan to let one of you exceed the games usual limits. Otherwise the game will tell the other person that your god is a cheat (and I think it does bad things to you in the game also)
It will take you abit to get into doing this by maps but it will be worthwhile. You will be able to donate your god designs to the RanDom program to pop up as surprises on randomly generated maps.
To do it you should make a copy of the map file. Such as, if you want to play on the Aran map then make a copy of the aran.map file named something like aran_special.map
Its a text file you you can edit it with something like WordPad or NotePad.
The important commands for what you want would be
5.13 #god <nation nbr> "<commandertype>" pre-select the god of this nation
5.14 #scale_chaos <nation nbr> <(-3)-3> Forces the dominion scale
5.15 #dominionstr <nation nbr> <1-10> dominion strength of a nation
6.4 #comname "<name>" overwrites the active commander's random name
6.5 #bodyguards <nbr of guards>"<type>" Gives bodyguards to commander.
6.6 #units <nbr of units> "<type>" squad of soldiers to commander.
6.7 #clearmagic Removes all magic skills from the active commander.
6.8 #xp <0-900> Gives experience points to the active commander.
6.9 #mag_astral <level> Gives magic ability to the active commander.
6.11 #additem "<item name>" give specific item to commander
Here is a quicky ref chart of all the map commands.
http://www.dom3minions.com/docs/map_qref.txt