I looked at the trimagnum also have the plans for the Trimuter I purchased back in the early 80's... didn't really like the design and it uses the rear sub assembly from an old Datsun 510 so the plans are basically useless now although he still sells them.
I looked at the newest one, construction pictures. That is so over engineered it's pathetic. It looks like he started building without a plan and kept adding things to overcome design problems. It's easy to engineer a complicated design, it's difficult to design a simple design. I like to keep things simple which takes alot more design work but is well worth the effort in the end.
Here are a couple shots of the rear swing arm assembly...


Not the best pictures but it gives you a general idea... rear drum brakes from my old 88 S10. The control arm bushings have a different slot arrangement on each side, one side adjusts camber the other side adjusts toe.
I'm working on the steering using a scavanged 79 Chevette rack and pinion which needs to be extended to match the A arm geometery.
The A arms are scratch built, assembled in jigs then welded.
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