Improved Geometry for GM Triangulated 4-bar susenpension

[Mutt's37Buick]

I have a GM triangulated 4-bar rear suspension from a 95 B-body that I plan to swap into my 1937 Buick (like the one in the picture).
Still considering a torque arm set-up, but also looking at keeping with triangulated 4-bar for simplicity and lower cost.
I already bought UMR Performance adjustable lower control arms with Roto-joints on the axle end.
I have read that it is best to have all arms the same length.
The standard upper control arms are much shorter, so I'm wondering if I should try to fit something longer for better ride, or performance.
Suggestions and guidance would be welcome.
Thanks