A whittler's club sounds like a great idea. It could be a lot of fun and a cool learning experience. I'm hardly a master whittler, so I can use all the help and guidance I can find. Id never whittled much more than a hiking stick before this year.
Aeneas - That's a tough question, just because there are so many types of whittling. Whittling something like a bird out of a piece of wood is much different than a ball-in-cage. The bird requires more shaping, while the ball-in-cage is mostly tip work. I love Old Timers for shaping, just because the sheepsfoot blade is so big. For intricate tip work, a wharncliffe whittler is my favorite, although the spine of any sheepsfoot can be ground down a bit to make it pointier.
As far as knife size goes, the size of your hand is the biggest factor. My Roberson half-whittler is very small, and probably would be hard to hold in a very large hand. A whittling knife can be any size. You just adjust the size of the whittling project to the size of your knife. Where my small ball-in-cage was done with a small block of wood, the same project could be done on a larger scale with an Old Timer (80T) Senior. Comfort and safety are the most important factors in choosing a whittling knife. The only real reason for me using a Middleman over a Senior is that the Middleman fits in my jeans pocket better.
I got my Boker carbon steel stockman today, and Im quite impressed. Thisll make a nice whittling knife. All of the springs are strong, and there is no lateral blade play in any of the blades. The Boker even came with decently sharp blades and good grind lines. Thats pretty uncommon in a slipjoint. I did touch up the edges a bit, and they took a nice razor edge. The bone isnt as green in color as Id expected, being more black than green, but the knife still looks darned pretty. I think Im really going to enjoy using the Boker. Its a nice medium between the Old Timer and the Robeson, with its smaller sheepsfoot. Excellent quality.