Most people are not aware that the correct lens board for the Wista has a centered hole and use the standard Linhof spec board, which is offset downwards by about 7 or 8mm. Wista themselves supply this offset board as standard. I was made aware of this a couple of years ago via a discussion on LFPF and confirmed it with Wista.
If you find that you use front fall very often, I can get you custom drilled lens boards with the hole offset according to your specifications.
Kumar