I have made many, many quilts with Fireside anti pill fleece as the backing and some Polar Tec. Only once at a customer's request did I put batting in. I think it makes it too heavy. However, long arm quilters like to add the batting because it helps stablize a stretchy fabric.
I prefer to do the quilts with fleece backing at home because the LAQ people tend to stretch the fleece which makes it pucker up when quilting is finished.
At home, I seam together as much as I need for width, first cutting off the selvages and using a fairly wide seam width. Lightly press the seam open and either baste the edges down by hand with giant stitches or just use a washable glue stick to hold the seams open (less bulk).
Then on a 30" x 60" table I clip the squared up fleece with large binder clips to the edges of the table starting with the middle of the quilt. I have toothpicks taped to the centers of all 4 sides of the table to help with centering.
Next smooth top of quilt over the fleece lining up the centers, etc. Smooth out any wrinkles and double check everything. Pull back the top a couple of feet and lightly spray baste ... very lightly. Smooth top back and pin the edges.
Keep moving the back and top around on the table to get all of it spray basted with no wrinkles. Pin the edges with safety pins.
If using stitch in the ditch, then do it now through the centers both ways and then continue back and forth around the blocks...first one direction then another to avoid distortion. Use larger stitches.
If using free motion quilting, then run some giant basting stitches either by machine or by hand through the centers of the quilt both directions and a few other places. Pull these out when your quilting is done.
Don't quilt too close together and use about a 3.0 or 3.5 stitch. Preshrink all fabrics for the top and the batting if you are using one.
This is just my way. Hope it helps.