I have a machine that looks just like this one, well not really. Mine is actually in far worse-looking condition, but only for now. My rebuild is moving along quite nicely, I'm hoping to have all the busted parts replaced, broken parts mended and all the dull parts shining and be pulling shots by the Ides of March.
The only info I can provide about this model is that mine has the brand name Formula on the side panel, and I have no idea what the ideal input pressure should be. I have found that the site cafeparts.com has sections broken out by brand and that the Wega section has great exploded diagrams of the internals.
Yours is certainly a nice looking machine.
Good luck and Cheers,