Mike,
This thread has some stuff that should help you. Tony Francis imparts some interesting observations on the bracing of the originals here.
I think you've seen the thread of mine on the Luthier Community Forum documenting the build of the acoustic lap slide I made for Colin Symonds. I can't comment on Weissenborn sound as I've never seen or played an original but I'm more than happy with the sound I get from my version and bracing. Colin is picking his Red Kite up a week on Saturday so he can give his view too. These are some of the most "fun" instruments I know to play so you are going to have a good time.
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Dave White
De Faoite Stringed Instruments". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010