How hard you start depends if you have to drive the car home or if you have a trailer
I use 4500 rpm and then floor the throttle and lift the clutch over about a 1 second period. With sticky 175/60 x 13 tyres and a LSD, a 3.77 diff , close ratio gear box and high torque race engine this gives me the quickest launch off the line. The Elan is relatively easy to launch compared to most car and i can generally get a jump on cars on the line or two in front of me on the grid when I get it just right
Exactly what happens in this 1 second period is hard to measure as I do it by feel, but essentially the revs stay at 4500 rpm and over that period of 1 sec I go to fully open throttle and the clutch fully in and the car moving without wheel spin, fron then on the car accelerates without clutch slip through the gears.
When I had a more conventional road based car that i was driving to the track or hill climb I would do a similar process but just a little more gentle - i.e big capacity but sprint spec engine, 155/80x 13 road tyres tyres, semi close gear box, conventional diff -- I would launch at around 3000 to 3500 rpm. I had a couple of donut failures and a diff output shaft failure when launching like this and converted to Cvs due to that back in the 80's.
cheers
Rohan