I've shot a few patterns with the RST Spreaders #7 1/2 shot in 2 1/2" 16 ga 7/8 oz (.015" constriction choke) & 2 1/2" 12 ga 1 oz (.030" constriction choke) & compared them to the 28 gm Poly Wad Spreader loads in the same 16 & 12 ga bbls.
From my limited & non scientific testing the Poly Wad 28 gm loads definitely opened up more than the RST but the Poly Wads had some mighty big holes in the patterns @ 20 yds. while the RST Spreaders opened the pattern about 1 increment in choke & provided excellent patterns @ the same distance.
I'm planning on using the RST Spreaders in both of those bbls for grouse & woodcock this fall but I've had the 12 ga .030" bbl opened up to .018" & I need to pattern it again.
I suggest you talk to Alex Papp or Morris Baker @ RST. They can tell you what performance to expect out of a full choke.
I think both the Poly Wad & the RST Spreader loads have their place depending on what you are wanting to accomplish.
