Springback formula is theoretically 1 / (Nsquared - 1) for N identical laminations. However springback is generally a bit less than the formula predicts for wood - probably because it takes a set.

I don't bother to make springback corrections for more than 4 laminations.

IMHO it pays to make a test run or two. For a canoe I needed to make about 25 laminated ribs, 4 x 1/8" pine. This was Algonquin Guideboat style of construction (plank-over-rib) so they had to be accurate. After some experimenting I found I got virtually zero springback after moistening the laminations a half-hour before gluing up with Titebond III which tolerates moist wood. Max dimensional error was less than +/-1/32" over the entire batch. The experimental tests saved me time and ripping waste by reducing the number of laminations needed.