GL
I am a big fan of Primaloft (Sport) insulation. I have used it in two hammock overquilts and a pillow. I also have at least three PL insulated jackets and three sleeping bags (two TNF and one Mountain Hardware). It does insulate better when wet (damp) than down.
When I made my 30* quilt I did do some quilting (about every 12" because I knew it would get tugged in different directions in my sleep). On my 50* quilt there was no quilting. The stuff I bought had a scrim and because I didn't know what it was there for, I pulled it off.
All this being said, lately I have been interested in
this Climashield Apex. They have been improving Climashield and I believe that it may have caught up with Primaloft. Also, they say that since it is 'continuous filament' it doesn't need quilting/tacking.
If you are looking for PL Sport with scrim, I know that Quest carries it as well as a few others.
Edit:
For quilting, I made a spacer bar from a piece of wood. I just guessed at the thickness of the insulation when squashed and added the amount needed to equal the 'claimed' thickness of the insulation. I then used that every place that I wanted to tack the quilt. Run the needle and thread through by one side of the board, go around the board and through the fabric again, tie the thread snug then slide the board out. You now have a loop that allows for the thickness of the insulation. If you use finer thread then you might be able to pull the knot through one layer of the fabric and into the insulation to hide the knot. I just left my knots exposed to the top. This board is about 1/2" thick to allow for more surface area where the thread could pull on the fabric.
Edit again: On my second quilt I sewed the edges through both fabric layers and the insulation but with the insulation on the outside - leaving one end of the quilt open. I then turned this inside-out so now the insulation is on the inside and all the stitching is as well. You now just need to sew the end shut. Be sure that you sew through the insulation when you do this to hold IT in place. Nothing wrong with sewing around the edge again (about one inch in from the edge). This will help hold all the more and give it a finished looking edge.
We'd be happy to see the finished product!