I generally run with DELOBJ set to 0, so the primitives are not destroyed along the way. Having them available can be helpful when you absolutely have to regenerate an object. Maybe you don't have to...
Sometimes, STRETCH will work like you'd expect it to on solids. Sometimes it won't. I have no idea why.
Failing that, some combination of the SLICE, COPY, MOVE, and UNION commands can probably help you adjust your object without regenerating it from scratch.
Mike Halloran
Pembroke Pines, FL, USA