Thank you AFairley. I'm in the same situation as you, I only shoot at infinity. Maybe I will modify your idea to the end that I will settle with just 5x the minimum focussing distance of each lens, to feed the algorithm something that it exspects. (I am shy to blindly mess with math that I don't understand).
It will leave the task of calculating the size of the target for every given focal length at that shooting distance. Would anybody know how to do that? How to calculate the target size for a given focal length and shooting distance to make that target fill 1/2 of the frame?
But even if that can be calculated, I see a problem.
E.g. the minimum focussing distance for my 24 mm Zuiko is 0.25 m, that would mean 1.25 m is the farthest distance that the algorithm exspects. Well that is still very far from infinity. Can this really work?
After all, the project will require considerable resources. I will have to have these targets printed and mounted, and then find out what is the cheaper procedure of these two: a- buy 2, maybe more softboxes to illuminate these targets evenly; my 2 Solux lamps can with some effort cover a max of A4 (210x294 mm). Or b- have a pro with a studio shoot the targets for me. I refuse to mess with ever shifting daylight for this task.
As I write this, I get the feeling that it will be easier to correct CA manually in ACR... (It is CA that I'm primarily concerned about).