Checked my local Home Depot and they have the ProPink insulation, but not in 1.5″ size (I couldn’t even special order it, they just flat out don’t carry it). They have 1/2″, 3/4″, 1″, and 2″. I was wondering if I could just use the 2″ insulation in place of the 1.5″? I’m sure I could also put two pieces of 3/4″ ProPink together, but I’m not too comfortable with that idea.
Problem with 2″ is you typically double up on the 1.5″ to get 3″ which fits in a 2×4 great. With a 2″ PP you can’t double up and if you just use a single sheet you have alot of airspace to fill with GreatStuff. I had the same problem as you and went with the 3/4″ sheets and just doubled and quadrupled up to get 1.5 and 3 inch pieces.
If you use the 3/4″ use expanding foam between the layers and you should be golden.