I can't speak for Canada, but in the US the glue is the same for sch 40 & 80, but which glue you use is determined by what diameter PVC you're gluing.
"Regular" is only for sch 40, up to 6".
"Medium body" is for sch 40 to 8", sch 80 to 6".
"Heavy Body" is for sch 40 + sch 80 to 15".
I know for aquarium use it's not as critical due to the low pressures involved, but if you use sch 40 & sch 80 in the same circuit, the pressure rating of the circuit is that of the sch 40.
Eheim Pimp #204.
58 gal planted Oceanic
Red Turquiose Discus, Japonica shrimp, assorted Blue Eyed Rainbows, Tetras, Hatchets, Danios, Rasboras
10 gal low tech planted Celestial Pearl Danio (Celestichthys margaritatus) & Emerald Dwarf Rasbora (Microrasbora erythromicron)