Hey I just had a brain wave! Oh that hurt. Anyway the former post about increasing rise gave me an idea. You could actually extend rise or fall by just turning the lens over. So if you need to increase rise you would position the lens so the hole was above center.
Darn now I have to make all new lensboards! Lucky I make them out of very thin plywood used for modelling. That and some flat black spray paint and I'm off to the races.