Yeah there's a thread on the SM boards somewhere on closing the end of an airplane wing that goes over the same technique.....insert a couple of isoparms towards the end and scale inward. Really, it just depends on the situation as far as what to do, though. If you're stitching, I wouldn't start with caps at all since it's just a part of whole. If you DO need to use caps, build the cylinder with caps at the time of creation....ADL, is right....planar trims can be a drag to work with i(especially if you have to translate the cylinder in some way).