If you ONLY have the finderscope in use, the 6x30 is the better choice. I like my 9x50, but I find that I have to sight along the outside to get my target into it's view to start with. Not very convenient.

However, if you use it in conjunction with a unit power finder like the rigel or a GLP, then I'd definitely go for the 9x50. The unity power finder is much easier to get a quick alignment with the target. Then the magnified finder becomes more like a permanently affixed low power eyepiece. In this case, you DO want some magnification and aperture to help you pick out those dimmer stars for star hopping to your final destination.

-Dan