Unfortunately the plans don't often give info on allowable tolerance. When I attached that angle to the tank I made it parallel to the baffle (measured using a straight edge clamped to the angle).
The sides of the fuselage (at the attachment point) taper in slightly toward the firewall and that is the only thing that might cause an issue if the angle is too far off from being parallel to the wing spar. I'd guess it would need to be out by more than at least 1/16" across the width of the angle to potentially be a problem. If yours is really really out and needs to be redone then it may be easier to replace and redrill the angle rather than the rib, or do some slight bending or shimming at final assembly.
Paul vS (yes I'm also a Van)
Building RV-6A #22320 O-320 FP. Wings and tail complete, fuselage almost done, working on canopy.
Flying my Aeroprakt A-22 STOL and the aero club's RV-9A while I build
Last edited by PaulvS : 12-21-2021 at 07:32 PM.