I'm struggling to visualise exactly what you want but it sounds like the sort of thing I'd script rather than try to achieve with wiring parameters. Scripting controllers is really quite straightforward and in my experience more reliable than titting around with the wiring dialog.
Hi everyone! I recently made a 3D model that need to be scaled in width and length separately with different measures. For this purpose I used a morph modifier, using one channel to target at the largest model and another one to the longest, so currently I have two channels that go from 0% to 100% (you can go beyond of 100…