Did you ever get the wiring correct on you Split Second? I have one and just did a complete flipper rebuild and re-wire and now i have strong, powerful flippers with all new parts. Let me know if you need some pictures of how i wired it. The original wiring was VERY strange (to me). It had a double-switch for the EOS, one switch ENGAGED power and one switch disengaged power, it was really strange. I re-wired to to match modern setups with the single EOS and it's all good now.

That is wired the way it was on purpose, so that the double flippers do not engage at the same exact time - one is a Split Second (sorry) after the other, to prevent voltage sag on the solenoid circuit. Almost all if not all double flippers on games from this era from Bally and Stern are wired this way. I usually install the double EOS switch but bend the secondary flipper closed so both flippers do activate at the same time for responsiveness reasons, but the secondary switch is still there in case future owners of the game want to put it back stock.