I found this disconnected and tucked away under the dash of an 02 I'm working on at the house. Never seen a duramaximizer like it. Customer bought the truck used and thought it was bone stock. Looks like someone was having fun with it at one time though:D
I run the sled puller as well. I really like it but it does have lockup issues under big power launches. If I could do it again I would go back to a 1055.
Heaviest I tow is a cooler in the bed, so I can't help there.
https://www.youtube.com/watch?v=vEdDZSrlq0c&feature=youtube_gdata_player
Spent a ton of time building a draw bar type hitch and my choice of metal was not sufficient. Main cross bar buckled and pulled out of the frame. Tore a bunch of stuff up.