I program my timers to have a 30 second delay before they go to flight rpm.

Yes.

This is what I do:     I bring the airplane to the circle, set up my lines, walk back to the airplane.  Battery has been pre-installed and the arming switch is out.
my assistant holds the airplane, and I plug in the arming switch to activate the electronics. the ESC gives back a series of audible chirps to indicate
that everything is ready to go.  I listen carefully to those audible tones. if I forgot to plug in the ESC to my FM-9 timer, the last tone is missing, indicating
that I messed up last time I made an rpm adjustment, and forgot to re-connect the ESC to the timer, or something else is askew.  I can stop now,  
go back to the pits and troubleshoot the problem, and  not be charged for an attempt.  If everything is OK, I signal the judges, they start the clock, I push the button to
start ignition sequence, and walk to my handle (do not run).  I allowed 30 seconds on the timer to do this. Once I get to my handle and am ready, I signal
my assistant to back away from the model.  I wait for the prop to turn, and begin my pattern.  I like the model alone on the field during takeoff as
I think it looks more realistic.

Ther have been folks who have damaged airplanes using the slow motor spool-up and flying off grass.

I use the medium spool-up and minimum delay.  My pitman pushes the start button when I pick up the handle, then holds on until the mtor sppols up enough to make thrust, then releases when HE thinks its time.  Motor is still spooling up through roll and liftoff.  On a grass field or on a windy day my helper will hold on just a little long than on pavement, but always launches before the motor is up to full speed. 

John,
I don't think the spool-up rate is as important as having the motor power pretty close to full power before release when flying off grass or in high wind. If you are flying alone on course or tallish grass you need to use a stooge that allows you to hold the airplane until the power is up so it will accelerate smoothly. Also, you may need to use a little bigger wheels. I went from 2" to 2 1/4" and have not had any issues.

Best,                DennisT

John H:
You may remember Alan Hahn who used to be on this forum but has since left.  I think he twice had incidents were during sppol-up his airplane got tangle up in the grass enough to get turned about such that he basically crashed on take-off.  Sounds like you had a near-miss that could have one very badly!

My Pathfinder twin was severely damaged when launching un-attended - and this happened to a trike gear on pavement.  My nephew was at the handle I hit the start button and walked away, thinking I'd see a nice acceleration to take-off speed.  However, according to the ICE data, the outboard motor spooled up just a little faster than the inboard - enough to get it turned toward the center - not good...