Some things to consider. Just adding tonnage by increaseing cyl size or pressure might not be a good ideal. I have a 6way knife wedge and a 5in bore cyl. Tonnage around 40tons or so, I havent put a guage on it. This splitter started out as a 4way with a 4in bore cyl. Split anything and everything except the narliest of large crotch whiteoak. I swapped the cyl to a 5in bore and then added two more knifes. Now for almost everything, this combination pretty much doesnt slow down, until I get that large narly whiteoak crotch. Cyl willl split it just fine, but watching the hbeam twist and bow will make you cringe. So much so that I lower the wedge and only do a 4way split on the really tuff stuff. I have my knifes stepped back so that the split is progressive, first knife doing the half split, second set of knifes doing the quarter splits and the last set making it a six way. This progressive splitting keeps the wedge from trying to do all six splits at the same time. I would suggest a similar progressive knife wedge for a 8way. This reduces the amount of splitting force required as well as reducing the stress on your splitter beam. I am building a splitter with a 12 way wedge. Wedge is a box design and the knifes are mounted in a progressive split. I will be using over 50tons of splitting force. Beam has been boxed and plated for re-enforcement. The wedge box will be braced at the top, middle and bottom to prevent beam bowing. Will this be enough tonnage and will the beam standup to the pressure, I dont know yet. I am trying to overbuild it and hopeing for the best. You can bet if it breaks there will be plenty of fireworks.