The one shot, homebuilt and Williams are all limited to dies that can only bend up to 90 degrees. Try building a shock hoop with that?
I use a Pro tool (full hydraulic) at work and a US Tool and Die bender at home that I added hydraulics to.
In order to get a clean 180 bend you have to get a 240 degree die.
I would never spray any sort of lube on either the main die or follower die again, what you should do is clean to tube well before putting it in the bender. When I first got my US bender I lubed the follower die and found that the lube itself worked like glue for holding anything that might jamb up and gouge the work piece and die.
If you do get a gouge in the die using a drum sander can remove it, weld a big groove in and resand.

Anyone who bends tube knows that when dies are new, tube will get stuck, knocking the holder pin out will free the tube. Make a few hundred bends and the tube will come out with a slight shake.

SD