Beat Offset to fader

Topic name might be a bit confusing but i'll try to explain.

I'm in the midst of creating a mapping for the Behringer BCF-2000. Most of my tracks are perfectly grided but i have a few older tracks ripped from vinyls with a little "flow" of the tempo and thus desynced with the beatgrid.

Now i came to a little idea in the meantime which would pretty much cover this problem.

What i would like to achieve is to have control over how much the playing track is offseted from the sync. I'm using temposync obviously. When the fader is in the middle ot would be neutral. When the track flows a bit off the grid i would just move the fader up a little or down a little to adjust. It would be awesome if the fader would reset to neutral when loading another track.

I tried to achieve this idea above by connecting the fader to the fine buttons from beatjump with little success. Also in the "out" section in midi there is something called "phase sync" which i assumed is what i'm talking about but routing it out to a ledring or a fader didn't result in anything.

Any ideas on how to do this ?