[Overdriven]

There’s plenty of free suspension geometry guides, calculators and such out there, start searching and reading. Sorry, I cleared my favorites list or I’d link some. Watch some videos or whatever if you need help there on the fab side. You can buy the same bushings that fit tubing like that kit you linked, ditto for the rod ends, and build your own.

You don’t sound enthused about making a giant notch so don’t do it. Notching the trailing arms isn’t a good idea in my opinion so don’t do it. You want to link it at some point so either build it yourself or keep stashing those pennies.