Tim,
If you built the wing stock the roll rate will be sluggish. That wing is really much longer than it needs to be for a great flying plane. The longer wing will also make the plane want to float forever on landings.

Mine has one rib bay removed form both wings, and the roll rate is improved quite a bit. The plane still lands like a trainer; you have to be patient waiting for it to settle in.

By the way, I fly mine with a Magnum 52 (54?) four stroke. (It's the 4 * 40) Also a nice combination.
Dennis-