How soon is soon enough

I have P-411 and I thought I should get prescreened by some p-411 providers in Vegas as I will have a window of opportunity. When should I send in the requests? 1, 2, 3 or 4 weeks before the time that I will be there? What is the norm? Thanks for the help.

As soon as your travel plans are all in order. Prebooking is the norm here in Vegas, so even a month in advance isn't too early. Best of luck to you!