After rinsing and drying them, I removed the membrane from the underside
of each rack. I know some people debate the necessity of this, but I
always do it. BTW, use a paper towel to get a good grip. I rubbed them liberally with the Galena Street rub from Penzey's. This is a pretty
decent rub mixture. I'm not sure if I'll buy more, since I have a recipe
that I like, but hey, I got a two cup shaker bottle out of the deal.

I smoked them for 4 hours (~220F) using whole pecan logs. I then wrapped
each rack individually in heavy-duty foil and tossed them back in the
smoker for another hour. I suppose you could just keep them in the oven,
since they don't get any smokier, but the oven was being used for something
else. During smoking, I sprayed them regularly with water from a spray
bottle that I use just for this. You could use a mop, but I find that, for
my tastes, really liberal application of rub and the light spritzing of
water give them plenty of flavor. BTW, don't wash off the rub, you just
want to keep the surface meat from getting too dry. I also placed a pan of
water right where the heat from the firebox enters the smoking chamber. It
held 4 cups of water and about 1 was left, so it's not a lot of steam
generated.
I separated them before serving and put sauce on half and left the other half dry.