Its hard to tell, especially as I have always had bigger/heavier machines and they are set in metric. For my stepper Bridgeport I cant actually recall the exact accel but I think its something like 50mm/s/s so for your imperial that would work out around 127in/s/s.
These numbers are however meaningless as they are on two totally different machines, different drives, motor weights types of axis etc etc etc.
What I would do is drop the accel by half and see if it makes a difference, if it does then start increasing again until you find the sweet spot.
Hood