i use a d'addario 13-56 set for my rgd which is 26.5 scale, so id say somewhere between 58-62. and yes, DEFINITELY a wound 3d string, which means DONT get either the EB beefy slinky or EB not even slinky sets. or you could, and just buy some 22-26 wound strings separately.
It all depends on what you like. I use a mix-matched set of strings for my drop B guitar, but I've found the best set is the D'addario 12-60 set, then replace the 20 with a 22w and the 60 with a 62 or 64. This leaves you with 12, 16, 22w, 34, 46, 62.
How much tension do you like? What gauges feel good to you at what tuning? (10-46 in standard, 11-49 in Eb, etc.)