I haven’t followed the whole thread, so forgive me if someone has
mentioned this before. The best stiffener I have found for lace is
spray paint, which is a great way to use up left over cans. White
works best to show even coverage, if you have it. Simply suspend the
lace from the inside of a cardboard box for a throwaway spray booth
and spray lightly. Several coats are needed, letting each coat dry
thoroughly. Sprue up, and cast as usual.