My main with plastic slides goes up and down a T track on the mast... at first I had to pull the thing down by hand to douse the main.

Now granted I am only on a 27 foot boat, so considerably less mains'l and less over all load. But, I found if I took a slide, covered it with a thin rag and saturated it with Sailkote and ran it up and down the track a few times... applying more Sailkote before each trip up the mast, my main dropped like it had lead in it.

I tie a line to a slide with a small loop and use the halyard to raise the rag covered slide... the same line is long enough to use as a downhaul to pull the slide down. I run this up and down the track a few times at least once a season and the main behaves beautifully. I have to pull a gate out of the track and pull several slides out to get this slide in for this "operation," but it has been worth it every time.

My main now drops nearly completely when I release the halyard. I have to pull down about the last 2-3 feet or so.

Saturate the rag with Sailkote... it has to be wet enough to do the whole track.