lol, you sound like me. Trying to figure out exactly what you can be hard. That's why at one point I had over 40 tanks running at once and 20+ in reserve. I got down to 1 for 5 years and now I'm back up to 4 (not counting my kid's tank). Now, my wife wants one and I have a rack that will hold eight 10g's that I just constructed a new air system for. Silly hobby.
Anyway, I would pick between the two. Cutteri really show their colors during breeding. That's when they look the best. Otherwise, they are a plain looking fish, but I enjoyed their personality. Dwarfs would also be a good choice for your size tank. I don't have a lot of experience with dwarfs (only a couple species of shell dwellers). I do know that some species of apistos do better in trios than pairs, but someone else will have to inform you on which. I can never remember.