I have used minky many times - it makes a very nice backing. I have not washed my fabric for the top when using Minky. if you used good fabric it will be fine. I have never had a problem with shrinkage.
I love the 505 basting spray and never have problems with that - - except that I spend a lot of money buying it. I now use elmers glue (learned that here on the board)
I usually quilt on my domestic machine using King Tut thread
good luck and share pictures when you are done
