For the underside, I have used stretched sprue (1/48th
scale) and liquid glue. Getting the sprue to the right width
is problematic, but not impossible. If you make enough of
the stuff, you can just pick and choose the right ones.
For the top, you probably don't really face the same
problems as far as *losing* the rib; you just might have
lost part of it, the shape, etc. I like to build it up
again, in that case, with gap filling super glue. An
accelerator like Zip Kicker makes it stand up more. I then
sand it until I'm happy. (yeah iteration after iteration)
So I'm not real scientific or precise when it comes to this
kind of stuff; I sort of use the eyeball technique.
---Stephen Tontoni
stonto@seaccc.sccd.ctc.edu