I went through SO MUCH of that with my 2001 GenII RMK 800.
My dad and I both bought identical sleds together.
He stayed bone stock because "a modded sled is a time bomb"
I moved my skid around and played with it for about 4 years. I found a pretty good optimal setting that was awesome off trail, for that chassis.
My sled was a 144 tunnel with 144 rails, 10t drivers (2.52 pitch), 8" rear big wheels, rear drop brackets, rail extensions to move the axle up (not back).
DO NOT run the track too loose when you move the skid back. Too much slack in front of the rails reduces efficiency AND can end up with a stabbed track.
What I found with moving the skid is there is a certain ratio of down and back that is ideal.
For every inch you drop the front, you can drop the back down two inches. You can move the skid back two inches.
So down 1, back two. That's the ratio.
If you move the skid back and the rear down out of the tunnel a couple holes, with no down in the front mount, you'll get very heavy skis. It will trench. You'll hate life.
Factory settings will leave the rail tips slightly up off the floor when sitting static.
When you get into moving skids, REMEMBER THIS RULE: You need those rails to sit FLAT when the sled is sitting static on the shop floor. FLAT.
Heavy skis will kill your powder days and handling off trail.
Remember, the best mountain sled handles crummy on the trails.
My sled sat 2" higher off the ground than my dad's identical bone stocker. He hated mine on the trail, but hated his OFF the trail.
He wanted to ride his sled on the way in, but then steal mine when we got off trail. LOL