starting car with grid

No you will not hurt anything with the jumper but why use that. I think the driver has far more control by spinning it over then turning the Grid on.

 

It fires right away. No measurable delay

 

This is one of the big differences I saw going from the Top Alcohol world to door cars. Almost all of the TA cars use a kill wire on the coil and almost none of the door cars do. Although rare, the kill wire gives me comfort that if someone turns the motor over, there's still plugs in it, and the odd chance the grid is still on, it's not going to try to 'hit.'

What worries me more than that is many roots cars will use a changeover switch to make it easier to start with a flywheel starter. If this switch is inadvertently left on the mag, the same situation could arise where the ignition was hot because there is no kill wire on the coil.

Kill wire on a door car is problematic because most coil locations are far from accessible, much less to pull a kill wire to start. Furthermore if you were to put one on in the pit, you leave the door open for it to be forgotten when the front end is put on, so the car won't start on the line.

To answer the original post, I have killed and started the engine with just the grid for a number of years now no problem. As a matter of fact, I have removed the kill switches from many of my customer cars since it's just another component to potentially fail and it is redundant. Kill power to the grid, the car shuts off.