One "shade tree" method to get an idea if yours are close or way off is to go ahead and mount your rings to your base and tighten them. Remove the top half of the ring. (This method obviously will not work with the vertically split rings.)

Set your scope firmly in the bottom half of the mounted rings. Using a flashlight, check that all surfaces between scope rings and scope meet perfectly and squarely without any gaps or unevenness.

Even when this all checks out good, when the top half of the scope ring is put on and tightened it can still throw it off due to the screw holes not being drilled perfectly in alignment. I remember when the old Redfield steel rings were made way back when, they were machined from a solid block of steel, then drilled and then the rings cut in half, and each matched bottom and top ring set were kept together and sold that way, so that each set was as perfect as manufacturing methods back then could make them. To maximize this benefit you would put the top half of the ring back on exactly the way it came off.