I know it took me a couple of hours to get comfortable on an XM when I did a demo ride. I didn't have any problems going from the Pro to the Cat and back but I just can't ride those Doo's.
It is impossible for me to imagine how the sled doesn't just tip over in deep snow, mine does. You also should not be yanking on the bars to lean the sled over. In the soft snow a little foot pressure and a little steering is all you need. The Axys for me is almost telepathic in its responses. I think left, it goes left. Get your feet up near the footwells, closer then you would stand on an XM. Use the bars just to keep your balance and use body weight and your legs to push the machine over while applying a bunch of throttle to drop the track. Done properly you can expect to fall clean off the first couple of times.
The big problem I see is this desire to set the sled up wrong to do something it is expressly designed NOT to do... the wheelie thing. I predict that as long as you insist on a wheelie set up, you will never get this sled to handle the way it was designed. I also fear for the rear suspension if you insist on riding around on the tail of the sled. Take a look at how they cut the rails back this year. There is a lot less strength from what I can see. Fine for the intended purpose, not good for wheelies.
You did buy the most extreme mountain sled on the market. To get to 408 lbs and work in the deep and the trees, the sled has evolved away from more traditional designs. You probably did buy the wrong machine for the riding you like to do. I know that if riding around doing wheelies was the way I wanted to ride I would have bought a turbo Yammi.