I would say to stick with the official v0.86 version .pde file, and update modifications to that. But it's up to you.
That code still works great with Arduino framework, only difference is the 20MHz crystal.
That v0.97 by Meelis is maybe just his own numbering from that 0.86 code. But you gotta ask him yourself.
What i do is just "based on version v0.86 by dcb", with following feature list whick i think is most clearest.
By using the official schematic, you are not going to lose about anything. Spare pins are thing that you may want to add, so you can later make modifications easier.
I have made my board full of spare pins and pads as you see (RX/TX/analog..):
http://mthtek.com/images/auto/mpguin...Guino-v1.1.jpg
But good idea for you