Hey everyone, I'm in the process of designing a rocket that could achieve high(er) altitudes. Of course, I want to make the rocket as small as possible, but maximize the height. I understand that the Mass fraction of the craft should be 0.91, where 91%~ is fuel/propellant, 6%~ is payload, and 3% is structural. My basic question is, assuming my initial weight(total) was around 500kg, what would be the best propellant/fuel to get the most distance? (cutting out factors such as air resistance and so forth) Thanks in advanced!