Just had a nose at your first post, as Benfrain says, try to buy the maxflow as it has everything you need straight from the box. Low pressure version.
if you dont have a gas thru grip or a vert adaptor you can put the blow off valve on the back of the marker. on my eclipse impy there was a silver allen head grub screw on the back of the impy. remove that (really tight!) and stick the prv valve there. it will still work fine
rich