I am using the 3/8" foam. One thing I forgot to mention is that you can tie in a little loop to the hook shank like on the wiggle minnow before you tie in the tail. keeps the tail from fouling and offers a tie in point for a dropper instead of on the hook shank.
I glue the hook in low for several reasons.
Makes the popper float higher like a dry fly.
Higher floatation is easier to see in low light conditions. Fishing at dusk or shady overhangs, etc.
Most commercial flys (Walts Poppers, Sneaky Petes)and including deerhair poppers are made this way also. It gives better hook gape clearance for more hookups and its easier to remove from the fish with hemos.
lastly, I just like the way they look!