The typical Indy spray bar valve cover has the tube located right up against the inboard side of the V/C, and they spray straight down onto the rockers, so you can still put the vac pump fitting pretty much anywhere you like.

If you can get lifters that won't allow the top end to be over oiled, then my preference would be to pushrod oil.
This assumes you'll be running rockers that are pushrod oiling compatible.

That being said, I have several customers running Jesel rockers with the spray bar oiling, and none of them has ever had any issues with that system.