Speaking of Tracks

Some were 1/32 and some were 1/35. M3 Grant, Lee, M4 and M4A1 as well as the panzers were 1/32.

The old Monogram were probably 1/32 scale.

Ditto on the AFV aftermarkets, I've used them on a Grant and a Sherman with great results.

Hard to imagine vinyl tracks breaking apart so quickly. I've got tracks on tanks that are decades old and still in one piece. Perhaps you used a weathering medium that is incompatible to the vinyl? Sometimes oils or enamels will react adversely with vinyl.

I've never used Friul tracks in one of my builds, ever. You can make a set of plastic indy-link tracks look just as good with a little work. Hell of a lot cheaper, too.

I advise against Fruil tracks for an M3 Grant.  US tanks had "live" tracks that were extremely taut.  The benefit of Fruils is that they show sag and weightiness -- totally inaccurate for a US tank like the M3 Medium Grant.  AFV Club or many other aftermarket companies make T41 or T51 tracks you want for the Grant. Speak to your local hobby shop dealer