I'd recommend spending the extra coin for a lighter can; it will minimize the POI shift as well as make the entire thing easier to haul around.
You might also wish to look into a PRI Gas Buster charging handle (the new BCM Gunfighter has some capability in that regard too). Or even just use RTV sealant around the charging handle (instructions to do this are on the internet). That will keep gas from blowing at you through the action. I use the BCM Gunfighters and they do lessen the amount of gas you get back in the face.
If you use contact lenses, I might also recommend some eyedrops too... I wear glasses and my suppressed ARs do dry out my eyes a bit from that gas. Not horribly, but a bit. With contacts it might be a bigger issue.