I have been looking at kitty nylon and original as well as venom and type X - I have ordered blueprint string and it was way to rough and after doing anything it would go all spaghetti on me! I also have ordered snake bite and the string was too skinny.
sOMEThING type-2 (allegedly coming to YYE any day now!) is my go-to.
From YYSL, the Ammo is much better than Type-X if you are looking for a bit of thickness. Type-X is fluffy at first but stretches a bit and in the end is on the skinny side, too. Ammo is like thicker Type-X.
I generally keep stock of Kitty Fat and XL. Both keep good slacks and are soft and they keep tension decently well. Those are my requirements for string generally.