Here is the fabrication and assembly of the bastard crotch system. We used cribbing to place the bastard valleys in space, both for scribing them together and for scribing in the jack rafters and purlins.

We isolated the elevation at the center of each bearing point, using the computer, and then constructed a wall system to place the valleys correctly. It definitely took some patience and time to get them sitting perfectly, but our cribbing system worked really well and did everything we had hoped of it.