Im a little late for this thread, but want to add a couple of thoughts/ideas.
As well as taking the breathers of the valley plate I have found that the rocker covers should have the breather hoses fitted on their respective inboard sides between the pushrod pairs of cyls 1/2 or 3/4 and 5/6 or 7/8.
I have found that these points are the least likely to be covered by any
oil surge during cornering etc.
On the Fords with front Dizzy I usually plumb hoses from the 3/4 & 7/8 areas into the catch tank. This catch tank is either fitted with breathers & pcv for wet sump, or in a dry sump referenced back to the Tank & Breathers. In addition to this the catch tank is fitted with a drain back line that fits to the adaptor on the block where the factory
oil filter mounted. The adaptor is drilled at this point to match what was the original
oil pressure drilling from the standard oil pump which is no longer used. As the front crank counterweight spins in close proximity to this area it creates a low pressure area & draws any oil that may have reached the catch tank back into the pan . Since using this system oil loss from the breathers or overboard has been virtually nil since the catch tank never really gets the chance to have any large amount of oil accumulate.
This system could also be used in a wet sump system with external pump/remote filter setup.