I don't worry about group level, but YES, I expect to be able to ride a representative model of the bike (or same geometry bike) in the size I am looking at to make sure it's comfortable and meets my needs and expectations.

Unfortunately, in this area, the only shop I know will do that is Performance Bike. They allow you to buy it first and then immediately return after it comes in if you aren't satisfied. (it actually continues into a full year, but not sure of the conditions). Otherwise you have to find a (super) shop that just has lots of inventory and generally even then only right after the new model year comes out, at least in my experience for my size.