Hi guys,
Thanks so much for your quick and detailed response. I saw the link
mentioned, but they don't mention much in the way of surfacing:

"Just to make sure you don't have a problem with twist. This is a
good time to do a loose fit. Can you put the boards together without
much of a gap? You should be able to close any gap with just hand
pressure. If you can't you should replace the crooked boards with
straighter ones - even if they are cosmetically inferior. "

Since some of the studs have more than 1/2" of warp to them, I'd rather
not just glue them up, leaving too much tension in the finished bench.

From your answers so far, I guess making a jig for the hand planer
might be one solution (I cringe at the thought of hand planing the stud
faces, since they have quite a few knots to them). I'll also run some
stud faces through the jointer (floor model), but it'll take quite a
few passes, given their warp. Here in the East Coast, we don't get the
cream of the DF studs. I'll compare the results of the 2 methods and
go from there.
It is tempting to leave the thickness at 3", but among other reasons,
SWMBO and I couldn't lift the darn thing for assembly.

Kin

p.s. Does the band saw have any role in this project? When would it?