I just assembled the Lead sled DFT to use to work up loads in my Encore and Knight. Anyone here use oneor know of any problems I may encounter? I got it to try to slow down the arthritis I have in my shoulders.

Yes - That ad on TV with the guy shooting the 416 Mag. He has 100 lb of shot on that thing. Don't do that. The recoil energy has to go somewhere. I have heard of guys putting too much weight on the lead sled and cracking their stocks. There was no 'give' for the buttstock.
IMO 25 lb should be plenty to substantially reduce the recoil of a ML.

I've never used one but one problem I could see is that you're going to have a different stock weld and eye relief because the Lead Sled holds your buttstock in an enclosed shroud. Therefore the rear of the stock isn't all the way in your shoulder. But it probably won't change that much from the LS to your real world point of aim. I bought a Caldwell Steady Rest NXT for the reason I mentioned above. It's nice and steady and I can still shoulder the rifle. But I do understand your reasons for getting the LS.

I don't plan on using addition weight. The thing weights about 25lbs. which should be plenty for what I plan to shoot.

i use my regular sled to shoot off of without any weight and it makes it a pleasant day to shoot with. makes sighting in a breeze.

I use 20 on mine and it makes the Savage with hot loads bearable. Chap

I have the Lead Sled as well. On my first trip to the range, Another guy saw me set it up and told me about the cracking of stocks and the flinging of scopes. I put about 20 lbs of ballast(weight lifting weights) on the sled and it worked just fine. I did notice that the front of the rifle was not as secure as I would have liked. I was shooting my Knight Vision. Does the front rest seem to grip the rifle on your "Sled"?

Mine has ajustable side ears for the front bag that when adjusted properlywill put pressure on the forearm. But I still haven't tested it yet. I plan to use it next week.

I have a friend that has become totally reliant on his leadsled. He uses 40-50# of weight. I rib him that he will have to take the thing hunting to ensure correct shot placement. I prefer a couple of seat cushions, sand bags or even rolled up gun cases...works for me.