Clarkimedes

How do you guys translate earth sized parts and fuel into kerbin sized proportions. I'm working on a mod that has a solid rocket booster. This booster on earth weighs 168,200 kilograms or approx. 185 tons, most of it fuel. This is way larger than the Kerbal stock parts. Should I resize them to fit Kerbin? Should I keep them earth sized and all proportional? What are the proper converions for earth to kerbin measurements? And finally, how much does a unit of fuel weigh in KSP?

So where do you find these modules? So far I have discovered where I could add in Agencies, or add in the text for the contracts, but I don't know where to add in the actual contracts. Has anyone made any discoveries yet?