"Bob" wrote in message
news:xSE6d.138449$D%.120838@attbi_s51...
I am patching holes left after removing some recessed lights. I know how
to
glue/screw wood strips as a back stop to attach the drywall patch to. My
concern is that the current plaster on the current ceiling drywall is up
to
1/2" thick in places. Rather than have to build up the plaster on the
patch
to the 1/2", would it make more sense to use a shim to bring the patch to
within 1/8" or so of the final surface before taping and plastering?
Would
the different thickness of the final plaster cause any problems?

I hope you don't really mean plaster. Some sort of shim would be a good
idea - otherwise you'll need too many coats because 1/2" is way too thick to
dry very well without distorting. But a setting compound would work good if
you have a mind to mix that up.