Just digging up an old thread cause im looking at nitrous for my 250 also but weve always run the fuel jets a size bigger if you want to be on the safe side. If you go bigger on fuel and watch your AF ratio then work your way down in fuel size or up in Nitrous till you get what you want. Always better to chance running rich then lean.
I would assume a 75 shot will give a stock 6er a nice kick in the pants?