I wonder if a potential solution, if you've got some mags that hit the long 9mm ejector and some that don't, isn't to use a mag release that drops the magazine down a tad bit?
Dawson has some that drop the mag 0.01" lower and that's probably enough to prevent mags hitting the ejector. That shouldn't be enough to cause feeding issues with mags that already don't hit the ejector and should help with those that are too long.
Of course the easiest and best solution is probably to buy whatever mags work in bulk.
But if you're like me and have several dozen 1911 mags that work in all your guns already, you arrive at the point where buying different mags for each 1911 to work is not economical nor sensical. Plus a mag release is an easy part to change and usually requires small fitting if any at all.
You can also file/stone the top of the mag release shelf/ledge and it will drop the mag down, but you can still insert too far then and that's where I find the bigger issue is.