If you want to attract more people who are new to the 60% scene I suggest adding a section on sourcing keycaps (as related to various layouts) in one of the first three posts.
The 60% form factor keyboard has been established for some time now. I think most people know about it already. In fact, I would say that, with all the major manufacturers releasing 60% boards onto the market right now, 60% is the growing trend right now.
However, the GH60 project was designed from the beginning as a DIY, choose-your-own-layout keyboard project. We will provide assembly for those who aren't comfortable building their own board, so that we don't exclude that group from participating and from their chance to own a GH60.
That said, sourcing keycaps is beyond the scope of this group buy. If there is a specific question regarding a certain choice of layout, I would be happy to answer it. Most of the layouts available would be covered by a standard base + mods + tsangan kit offered in the many keycap group buys going on now. Poker layout would not require the tsangan, and ISO would of course require an ISO kit.