Which tile cutter for 460mm marble tiles

I'm about to tile my kitchen with some ebay bought marble tiles. The tiles are all 460mm square but vary in thickness from about 14 to 22mm. I intend to lay them in a diamond pattern so am going to have to make quite a few long diagonal cuts (quick calculation tells me it must be about 650mm Hmmm - longer than I guessed). I have a standard wet wheel cutter which is theoretically capable of cutting them but with zero accuracy as the table bed is about the size of the tile, so there would be no guide. So the question is. Does anyone have any experience or suggenstions? What to hire or buy, any experience of the radial cutters as they would seem to be the most appropriate - if I can find one big enough. Thanks in advance. Dude