What delay in millisec for D.A.F.?

What delay in millisec for D.A.F.? Hello fellow stutterers. Does anyone of you have experience with DAF (delayed auditory feeback)? If yes, what delay in milliseconds do you set the app/device to, to help reduce your stutters the most effective? Curious as to how wide the general used spectrum is. I’m more than happy to hear your opinion/tips/remarks on the DAF-tool as well :) Thanks in advance!