All circuits have multiple grid markings for bikes, single seaters, saloons/sports ets ( 1 x 1 grids, 2 x 2 etc) but usually one startline
Spa actually has two startlines, the "F1" startline along the top straight and the "endurance" startline down the hill by the endurance pits. The F1 start was used for the FIA GT's for the first time last year.
