Lister,
Personally I had no problems doing my conversion on a Super Cub and then joining a group running a Vagabond. Actually it was the other way around. I joined the group and then did my conversion. This didn't seem to concern any of the members as I has to be voted in.
What type of tailwheel are the hours requirements groups running? From my personal experience of the Vagabond, I would say that I suspect building some hours in a docile taildragger like the Cub family before stepping up to something more demanding might be a good idea. Even a 65hp yellow peril can still become a handful. I say "I suspect" as my experience is thus far limited, but not uneducational.