I no longer have the operating instructions, but I think I can remember the following, as I recently assembled the table:
This does not mean R5t, but RST for perform reset. I meant press and hold the up and down buttons at the same time until the table is fully lowered. Somehow like that, no guarantee :-)
The dimensions differ in the maximum height.
Twain: (WxDxH): approx. 168 x 60 x 125 cm
Melville: (WxDxH): approx. 168 x 60 x 119 cm
The Twain also has one more lifting column and is therefore heavier.
I have a 200x90 16mm screen printing plate in my home office and a 200x100 press-fit plate in the office. Including the equipment, I'd say they can both withstand quite a lot.
But it is certainly the case that the upward sensitivity would have to be reduced manually.