You can buy the platen lock levers from anatol, should be in their parts store but check that you get the right ones for your machine, they seem to do a lot of revisions there and don't keep track of it, i.e., there may be two different parts from different casts but given one part #.
Offer's still open if you want to pm me and I can call or skype you and walk you through getting the press into parallel. With any manual that has adjustable off contact with "camber" you are basically going to get your platens all one one plane, the print heads in plane to the platens left/right or in the short direction of the screen and then you will need to adjust the front/rear or long direction of the screen almost every time you set the press up, depending. Presses with the camber adjustment just do not hold that adjustment very well given all the raising and lowering of the print heads, imho it's a poor design that is unfortunately used on a lot of machines.
Anyways, if you keep everything in close parallel your pre reg can start to really do it's thing, same goes for automatics.