the j-mount works quite good with this dish (I use a j-mount and channel angle-iron supports for extra secure mounting to keep the top part plumb) and then I put my hh120 motor and the dish on top of that. I believe the j-mount will even plumb up if you put the foot flat on a ground on a flat board. If I pick up a second 120cm dish, the foot will be on a flat surface rather than an upright surface like my first 120cm install.
and to all, after you get it, check out the fortec star 120cm thread(s) on this site for some easy mods that will make your dish really perform much better than it would as factory constructed.