Gear is a personal preference thing, so you'll surely get a lot of different answers depending on who you ask. For general use, I'd just get the Wallnuts, and later supplement with the Offset nuts. I actually find that I use smaller nuts more often, so your best bet might be getting the 11 Wallnuts, and later supplementing with the smaller Brass offset nuts for tricky thin placements.

Another option might be to lead on a friends rack, and see what works for you. This is really the fastest and cheapest way to learn your preferences if you can find someone to climb with.