In examining the Solidworks parts I noticed that the cylinder is larger on the new version than the old. I emailed Julius about this, and he replied that the split beam version is 1.5x larger than the previous. That means that the cylinder is 218mm or 8.5" long. I think building to this size would be a challenge for most. My plan is to build the engine, but I believe I'll use the V1 model plus the V2 beam that I'll scale back.
The V1 cylinder is 130mm or 5.11", still a challenge. If I can find appropriate size hydraulic cylinder tube with a honed ID I'll use that. Bore is 45mm (1.75"), but I suspect that's larger than is really needed.