I have downloaded some fun and interesting mods that add all kinds of creatures and items to the game, so far I'm pretty happy. One thing I've noticed is that while Golden Saint and Acended Sleepers were heavy hitters in vanilla, some of the new creatures I encounter make them look like middle-school bullies. However for all the trouble and grief I go through to actually kill one of these new creatures thier trapped soul is only worth 100-150. The flip side is that some of the new wearable and wieldable items I'm sporting have 500+ enchantment points. So I thought I would just go in and make a few adjustments so that there were bigger souls to catch and bigger gems to receive. Is this simply a matter of adjusting the soul values or is there a catch somewhere? I really don't want to have to spend oodles of time and energy modding Morrowind, I'm busy enough with all my other modding projects. In fact I really should have learned my lesson and never even put the CS on my computer.

You can simply increase the size of the soul for the Creature, yes.
If you increase the size by a lot, trapping them will probably require that you have Azura's Star.

Thank you Pluto, I was hoping it would be easy.
Does it cause any problems to increase the size of the soul gem? I somehow got it into my head that it was somehow bad to do, but I cannot remember where that came from.