Need Help!- Timing M7/M9 on/off?

[Gashmore]

Unusual situation. I have a piece with 1000+ 1/8" holes that need to be filled with colored epoxy. (Double 12 Domino set) I have an automatic dispenser that drives a syringe that I plan to mount on the Z axis next to the spindle. I figure I can use one of the unused outputs (like M7/M9) to control the dispenser.

My problem is the on/off cycle to fill the hole is only about 200-250ms. How can I accurately control the timing? (Running Mach3)

Will this work?
F30 (Set feed rate to .10" in .20 Seconds)
G0 Xxx Yyy Z.1 (Locate hole)
G0 Z-.10 (Lower the needle into the hole)
M7 (Start epoxy flow)
G1 Z.010 (Retract needle)
M9 (Turn off flow)
Z.10 (Retract to clear part)

[chucker]

why not just rapid to the hole then into the hole then M7 dwell(G04) then rapid up and over to next hole and repeat

[Gashmore]

That would probably work better. Just that I have been filling all those D#$%ed holes by hand and if I don't put the injector needle dead center down in the hole the epoxy bridges over and leaves a bubble. OTOH, the machine has a lot steadier hand than I do.