Gari,
if you go to the LF homepage you can find 4x5 cameras comparative page with an article about the AS -F line 4x5 camera. The old and new lens board should be compatible. I think it is the same for 6x9 models too. In such a case you could use a Horseman 6x9 RF holder on Arca Swiss 6x9 adaptor. The same would be for a 6x7 Horseman RF holder.
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