I removed the head and placed a bubble level on the top, and noticed a bunch of variation at the points specified in bed.g. Results are easier described with the video: https://youtu.be/VbzuqFZhGNA.
The tilt made me think it was an issue with the X-tower because of the deviation opposite it, so I checked the carriage and head effector more closely, and found that the threaded shafts that I'm using to attach my tricklaser carbon rods, (the version with ball links, not the injection molded ball links) are being bent by the way that the Rostock Max V2 carriages and effector attachment points are made.
I'd think that bend is a problem.
I've gone about replacing these components with the injection molded ball link versions to remove this incompatibility in the design.