I also did do some acceleration runs with my single-speed early-'70s dirt bike. It was not all one make; it was a Schwinn frame with parts I added on- rims, saddle, handlebars, etc.
As you said, being one speed, there was no time wasted shifting, but it did take longer to accelerate off the line.
I used to know the gears in each sprocket. I think it was 1, 3, 5, 7 and 9 for the smaller front one and 2, 4, 6, 8 and 10 for the bigger one. My older brother may remember since he also owned several 10- and 12-speed bikes.
I do remember that the gear changes did not go 1-2-3-4-5 with one sprocket like many people thought back then.
Cadillac '69 Fleetwood Brougham, '76 Cadillac Fleetwood Seventy-Five Limousine, '95 Lincoln Town Car.