What size rubber line do I need to get to go over the hard vacuum lines without leaking? Everything at the auto parts big box store is too big or too small.

Well, car turns off now. Ignition switch was not at fault, the switch wasn't getting vacuum. $15 HF vacuum gauge saved the day. I can get 50 cm from the line to the brake booster, pretty much everything down stream from that is only giving 20 cm. By the time you get to the 4 way that runs to the hose on the ignition switch, you get like 2 cm. I can get okay vacuum to the source on the 4 way, so I think there's a leak from either the clear/blue line or red/green line on either side of the brown hose that runs to the ignition switch. I don't know what either of those lines do though. I ended up running a line directly from a plugged t fitting on the brake booster line to the ignition switch. A temporary fix. I think I've got just a ton of small leaks from all the old Y and 4 way and T fittings and by the time the hoses get to the ignition there's nothing left sucking.