Not really. Masks are inaccessible to expressions and hence one would have to write a lot of code to reconstruct the underlying Bèzier formula and remap the percentage. Simply keyframe everything by hand. It may be tedious, but it's still a faster way to get there than brooding over how to do it smart-assy with expressions, convoluted scripts or whatever...
Thank you for your quick response, seems likely. I will reduce number of masks by using less several strokes in illustrator. And maybe there is a way to automatically join paths chronologically (endpoint of path below to startpoint of path above) in illustrator.
But what i keep in mind is that the stroke effect itself does exactly the same: it uses different masks sequentially as a motion path to locate a position, to where die path is drawn. Couldn't it be possible in the same way to move a null or a layer? Or how does the stroke effect face this "problem"?