Ah ok, now I understand the central point of your question ;)
Well, I'm sure that someone can argue otherwise, but I would say that there are more important things to worry about on a Delta that affects the print performance. As with many Rostocks/Kossels/etc., the effectors and mounting pieces are printed, so I wouldn't say that those parts align the hotends to exactly 90 degrees. Very close, but not exact. As long as the mounting orientation is not changing and the non-perpendicularity is not obvious to the unaided eye, then you shouldn't have to worry. I, for one, have a RostockMAX with a modified, printed, effector and a printed groove mount. All screws are tight, and I've never even checked its squareness.
I would concern myself more with the towers and arms.
Good luck!
Well, I'm sure that someone can argue otherwise, but I would say that there are more important things to worry about on a Delta that affects the print performance. As with many Rostocks/Kossels/etc., the effectors and mounting pieces are printed, so I wouldn't say that those parts align the hotends to exactly 90 degrees. Very close, but not exact. As long as the mounting orientation is not changing and the non-perpendicularity is not obvious to the unaided eye, then you shouldn't have to worry. I, for one, have a RostockMAX with a modified, printed, effector and a printed groove mount. All screws are tight, and I've never even checked its squareness.
I would concern myself more with the towers and arms.
Good luck!