A little info about soul gem uses... : The size of the gem doesn't matter, only that it's a soul gem. Also, the containers don't use up the soul gems... they remain. So you just build up the soul gems, and when you want to change effect, just take them back out, and put in the number you want. And it's the putting in that matters... so if you put in twenty and then put in thirty, your value should be thirty, not fifty. So you want all the soul gems to be the same kind. All petty and empty, or all grand and filled, doesn't matter, as long as you can put them in all at once.As for the effects, they're in roughly alphabetical order as they appear in the creation kit. So effects are mingled according to alphabet (so firebolt comes before raise dead, but after dread zombie, and VOICE effects come near the end:::.............how to access the demiplane and what to do... 1. After acheiving the rank of archmage, go into the archmage quarters. Look at the bed. Turn around 180 degrees. There should be a glowing gate. Open it to travel to the Archmage's demiplane (you have to have archmage key).
2. There will be 3 available spells... Archmage Spells Ayem Bedt and Cess. Take them, learn them like normal spells.
3. Instructions on crafting the specifics of the spells are in the journals by where they were found.
4. Short over-simplified version of what's in the journals: Add a soulgems in batches to the repositories by where you picked up each spell to change what that spell does. The type of soulgem (filled or unfilled, grand or petty) doesn't matter. What matters is the number added in a single batch:::.....you can also get this mod on nexus. http://skyrim.nexusmods.com/mods/25081/

Naj pretty much covered it.

@lil joshu there is still more to cover right. You said these things in the comments section so I copied,pasted and edited them into here. They had useful info. You are the developer of the mod you know everything (maybye) about it.

Actually, I was in the middle of a major revamp awhile back and lost everything in a harddrive crash, so honestly, I can't remember half of the things, due to getting "what is" and "what might have been" confused. So half of what I would write might be wrong, and I'd really, to get it right, have to get a character through the mage's guild again (lost my mage character in same crash). So, honestly, not sure I do know everything about it anymore, lol.

:| ... well dang