T shirts don't fray

I didn't notice the part where you said you were using T-shirts. Yes, the edges will curl up somewhat, but you will need to check it out to see if you like the look. It's not so bad with fleece, because it's thicker and fuzzier, but I still prefer homespun, flannel, or corduroy for rag quilts.

I have made rag quilts both ways. Some fray in front and back and some smooth on the back. There is no right way.

Sounds like you have a good handle on it! Welcome and don't forget to show us the finished product!!

Missouri Star Quilt Company has a tutorial on making rag quilts. I watched it before I made my first one. Good luck with yours.