Even though I own both machines, I can't answer your questions because I was only able to get about an hour on my Deleon before the first snow fall. I would however consider the Deleon a few steps up from the Ace. Don't get me wrong, the Ace is a great machine. Both actually weigh about the same so that shouldn't be a problem.
I too have had 3 shoulder surgeries and I totally understand about the weight of a machine. I have an omega 8000 and really really love that machine. I liked it so much that I bought a T2. The T2 weighs more than the Omega but because it is so well balanced, you don't notice it a lot at all. If I had to pick between those two, it would be the Omega with the DD coil because it can notch in nickles.
With the Deleon, the short time I had to use it, there were a few things that I liked about it. I ran across one signal that showed multiple bars from nickle on up. Most of the time I would have passed that up as trash but because the signal was so good and so strong I decided to dig. I found a small cache of 7 coins in the hole. 2 quarters, 1 nickle, 1 dime and 3 pennies. That really surprised me because the machine basically told me that all of those items were there.
It will suffer from overload signals if the coil is too close to the object, closer than most other machines, but all you have to do is lift the coil straight up a little and let the machine do it's work. It really is an amazing little machine.
I can't wait now until the spring to get it out again.
Best of luck on your decision. I honestly don't think you will go wrong if you do go with the Deleon.
Good luck to you and Welcome to the Forum!!