A quarter inch off in axle to axle isn't anything to worry about. When it gets to about 3/4" to an inch, it needs adjustment.

If you've got your weight backed way off, it might take a full turn or more to get the tiller measurements to move. In fact, it sort of worries me when you say the draw weight is at minimum. Don't take any more off the top limb. I don't know how much more bolt you've got in that hole and it really gets exciting when you back a limb bolt clean out of the riser. [:-]

Make your adjustments with the bottom limb bolt. It will likely raise your draw weight a couple of pounds, but it's better than taking the bow to the shop to have it put back together.