BC, What does a 'star' image look like at say, 150 x/ 200 x? Do you get good, even diffraction circles either side of focus? If not, then adjust collimation whilst on the star. Try about a mag 3 or 4.
Seeing has a lot to do with how the image looks, & how much mag you can use.
For a simple collimation guide > (
http://skyandtelescope.com/printable...rticle_790.asp)
Try 2070 (Tarantula nebula in LMC), as a starter. Should be able to resolve some of the central area.
If you're having trouble collimating, I may be able to assist with the basics,but read/print the article first.
HTH.
L.