I may not be an engineer, but I have seen and used a number of different hydraulic presses, and I don't think you want to go with a larger ram. The frame looks like it may or may not just be enough for the setup you have now.
One shop I worked at someone was pressing something supported in V-blocks, one of the blocks exploded, that was not a good picture.
There is a lot of force involved, and if something fails it can be quite dangerous, don't take any unnecessary chances. You could buy a really nice commercially built press for less than a hospital bill..
Grigg
