Batting can really shrink. I buy big rolls of warm and natural. I don't always prewash my fabric but I cold wash and dry the batting in the dryer. You can always ' quilt the snot out it' if you didn't prewash. That was my FMQ teacher's expression.
I almost always quilted the big quilts on my home machine Janome 6600. Sometimes in three pieces. For me it was much easier to do that than quilt as you go. However I FMQ and you don't have to turn the quilt like you have to for walking foot quilting. That makes a big difference. I got a used sweet sixteen last year but because of all the booms I've only used it on one lap sized quilt. I will be doing two more in the next couple of weeks. It was a very easy transition for me.
i think I'm going to make the big jump and join both booms. I need a lap quilt too.
Janice if you aren't going to send fabric you should give us color choices so we can 'surprise '' you with more squares. I think everyone did their best work for you. I wish now I had put everyone's name on my square; it would've made a great square for the back of the quilt.