Sam, how about drill and tap the #1 and 4 throttle adaptors after the throttle bodies to replicate the OE setup in the AE101/111 for dual supply to the brake booster?
This would be better for brake booster pressure in comparison to the T3 4x 2mm nipples surely (even with vacuume canister).
The Blacktop only has a 2mm slot milled from each throttle between the head and manifold for the throttles to provide vac to the Map sensor.
If you haven't got a blacktop manifold there (or seen one) shoot me a PM and Ill send it over.