Whats wrong with 28??????
If I had a regulated mod of 50watts or less. I really don't think I would need any more wire than what I now use with my Mechanicals. Mainly becasue I would build to the middle of the mods power range. I use 32 31 30 29 and 28. I build only single
coils although I do prefer twisted wire builds. BUT I also vape at 20 watts or less.
I suggest you start with a coil building calculator like Steam-engine.org. Figure out the coils you want to build then buy that wire. best wire is going to depend on the vapor you are looking for than the mod you have.