Yes spraying after the launch is easier on parts. And especially if ya bring it in gradually. Plus it's another tuning devise.
The <span class="ev_code_RED">Schnitz</span> progressive timer is one of the best out there. I used it for years and really like the adjustments it has. I went thru 2 N.O.S. brand timer units. Cost me a round at Orlando in 2001.
Just put a WOT switch on the carb and wire it in.