I was thinking someone the other day said the MSD recommended ballast is 0.8 ohms? I'd start by ohming the coil half of the 4 terminal ballast & see what you get & you can add a blue wire loop at the brown wire end just like there is at the other end to make it a parallel circuit which will drop the resistance even further if need be. On one I had it had 1.6 ohms on the coil side (way too much) and 6 ohms on the other side & after making them parallel I got 1.1 ohms which was close enough for my app plus keeping the 4 terminal ballast in the 4 terminal harness keeps a clean look & you can actualy sub in 2 singles as their width together side by side is the same as the 4 terminal ballast so you can mix & match plus parallel bypass if needed to get the ohms you want.