Sag can be set to anything you want its personal preference but the recommended range is about 20% - 30%
At 30% the shock will be more compliant and produce more rear end grip but you could end up bottoming out more or rear end might bob more climbing.
at 20% the shock will bob less when climbing and sit up in its travel a bit more but then might not give as much grip as before.
Have you got one of those DRCV shocks too? I demoed a Fuel EX and Remedy with DRCV last year I found I was using up all the travel quite a lot too but it never felt harsh on either bike so I just ignored it and carried on riding.
I was also told by the shop I demoed the bike from you need to cycle the shock (bounce up and down on the bike) a few times after pumping it up and then measure the sag. The different chambers need to equalise their air pressure.