Those are all moethods I tried. I am still considering making a hydro forming machine so I can do some interesting things with barrels.
But, alas, this is not the exact process I use. There is considerable force involved... Something on the order of 3 - 5 tons of pressure, but my method is purely mechanical.
Of course I could probably do the same thing using hydraulics, if I had a hydraulic pump, space and the wish to deal with the increased PITA factor.