need help adjusting challenge requirements for different planet scales

[sturmhauke]

I run the Shuttle Challenge v6 series, and there has been some interest in doing the challenges at other than stock planet scales. Namely, RSS, which if I'm not mistaken is 10x stock scale. So far I've just been winging it, but what I want to know is how to adjust the mission specifications (orbital altitude and delta-v requirements, mainly) in a systematic way. Let me give you an example.

STS-3 involves launching and assembling a space telescope. Pilot level is just getting it to any stable orbit. Commander level is getting it to a 550+ km circular orbit inclined at 25-30 degrees. When I flew the mission at Commander level, the total delta-v expended was roughly 5000 m/s. So if someone runs the challenge in JNSQ (2.7x scale), or RSS (replacing Kerbin with Earth), or some other scale, what should the minimum altitude be to make the challenge proportional to the scale factor? Specifically, is there a formula I can use to at least get a first approximation?