Every rider is different on how they like there sled set up. Best thing to do is adjust everything one way then go all the way the opposite way, se which way you like best then fine tune from there.
first thing you need to do if you havent is install from arm relocate brackets from amp. if it's bottoming out tighten springs, if not loosen it up. limiter strap will determine how high the skiis will lift.
if the sled has many miles pull the shocks off and take in for service, should be about $40 each.
If you want adjustability that actually does something then put a Timbersled suspension in there and throw out the stock. I absolutely loved my M7 (daughter still rides it) but the stock rear suspension really was crap in those things.
yea if i had 1500 just sitting around i would drop a new skid in there but thats not really and option at this point got to work with what i have and i also have looked for the relocation brackets before and never found any they way my suspension is right now under my weight is that the skis rarely come off the ground i have also read that the limiter straps are what control that but the ones on mine are tight and it looks like the are as far apart as they can go also all my rear shocks were recharged before i bought the sled