I use a lead sled a lot. I also use a heavy solid adjustable tripod rest for the fore end and a bunny bag for the butt.
Most people use a lead sled without using their heads. They use it as they bought it.
The butt pad on the sled isn't very forgiving. It needs a bit of help. I use a high durometer piece of foam. It isn't something that you can just pick up anywhere. It should be just flexible enough to squeeze slightly with your hands.
The above posters are correct. When the sleds are to heavy and there isn't enough recoil compensating material in the butt socket, all sorts of nasty things happen to the rifles and their accessories.
Split stocks, screwed up scopes etc.
The rifles aren't intended to be fired with their butts against an unmovable object. The scopes aren't meant to be mounted on non forgiving rifles. Especially the cheaper lines.
Go ahead and use a lead sled, just use some common sense.
Lead sleds, like bunny bags and bipods, have a learning curve to use them properly.