I Just let the tubing lead where it may--into some form of triangulation/non dead-end or interference! Ran into a bit of an issue the other day when measuring for the new right mount tube.
At some point years ago i set the right upper side rail more inboard, (when viewed from the front) which made that corner sit back further too. Was the source of my left side rear shock always feeling much softer than the right even when setup identical and swapped for testing. Drove me nuts. I'd park after riding and it would sit crooked. About a 7 degree shock inclination difference. Apparently I never measured the 3rd side of the triangle to verify.
Due to that, I had to pie cut some tubing to shift things a bit and I've got an asymmetrical pair of rear upper mounts now. But the numbers that matter--shock placement are correct as ugly as it looks.
Meantime, that strapped in cross tube has been installed, as has been the outside vertical tube tying the corner together. Things will get done quicker now that I'm past the mounts.