Debating if 2 or 3 prototype machines is worthless from my point of view.
The Cabinet / Backbox (apart from the decal design and the trims) won't change dramatically.
Red color trims are announced since a long time, decal artwork as well. Here the pinsiders had the most influence, I can remember discussing to reduce the various SkitB logos around ....
It was quite early designed in the shape / size it's right now
So to keep it (pls don't forget it's a non profit project) on the price level which has been agreed (and that's what Kevin did from the first minute compared to other well known manufactures!) I'm personally fine to have just 1 or 2 protos up and running. For me it's important that I see any progress during the development phase, not tons of protos / early versions .... as done by other well known manufactures and a stable price to plan accordingly.