Daniel,
Congrats on a first shot. You'll see the feverish obsession grow more and more as you go :] .
Some thoughts:
the trails could be shifting because of wind? or as David says the mount itself.
Good drift alignment will make a big difference I have no doubt
you may want to check the obvious (i've ruined many a shot having forgotten to check the basics) like any cables dragging/getting caught up, check the balancing (some say keep it a fraction heavier on the part that is rising (be that the weights or the scope depending on where you're shooting)
you can make your own Hartman mask :
http://www.iceinspace.com.au/index.p...63,187,0,0,1,0
looking at your first shot , you'll be there in no time
cheers
frank