A 1/4 in axle offset is kind of pushing it. There are a lot of angles to think of caster, camber, toe, toe out on turn, rear thrust angle, and more. That is not to mention the driveline geometry (drive shaft, u-joints, etc.) that should be considered, due to the axle not being square. Just because a vehicle will align does not mean that it will drive and handle properly. It could be difficult to control at speed, or it could be fine. If it were me I would probably leave it for now, complete the project enough to put it on a alignment machine and go from there. Once you are at that point and you verify that the rear end is square, you will have a more positive reference point for adjustments.
Best of luck.
ASE Master Automotive Technician