You do realize that painters cloth will more than likely shrink and wrinkle badly if and when you wash it ,don't you??
Since you're already using your roller foot,i don't know what else will solve the problem,but if you have an even feed foot,similar to roller,try that.
kathi

Thanks for that tip about the shrinking and wrinkling. I have already washed and dried the canvas and the linings. They actually came out much better easier to deal with than I was anticipating. I didn't dry 100% in the dryer,just put it on the "less dry" setting. I don't have a roller foot. but I'm dealing with it with my walking foot which I think may be the same thing as the even feed foot

If I'm dealing with a very stretchy fabric, I will sometimes do a multiple stitch zig zag over just the fabric itself first to help stabilize it, and then stitch it to the other fabric.

@Annie: Do you mean a dble zigzag? What stitch length do you use? Thanks... I may try this this w/e

It looks like this

I use whatever I think will give the fabric enough support...start with the default and see how it goes.