Got a tip from tyer Derek Young on another site regarding the Foam PMX. He suggested that for multi-layer foam flies to skip the Super Glue and tie the layers individually with thread only; have to admit that with 3 layers glued up things can get a bit stiff and make tying somewhat more challenging so I figured I'd give it a shot.
I've seen one of his patterns, the Yakcaddis, tied for the big October (and those are the colors I'll use here) but it sure looks like it could be used as a stonefly/hopper/attractor by changing size and color. Biggest issue for me on this fly was maintaining proper thread tension - got to walk a fine line between too tight, which can cut the foam and not tight enough, in which case I end up with a "spinner" (and not the mayfly phase, either).
hook - Mustad 9671 #8
thread - Uni 6/0 camel
body - 2mm foam (3 layers)
wing - elk hair
hackle - brown
legs - medium rubber barred brown
mash barb and wrap rear 66% of shank with thread back to point above barb
taper the butt ends
let the butt extend hook gap width past the bend and tie in (2 firm wraps)
place 2nd layer on top and repeat
pull foam up and position thread for 2nd segment
and again up to 66% mark