Any of the PCV rattle-valve cars can have excessive oil consumption due to that baffle. Not sure about the holes - never seen one pre-2000. BUT, some tough epoxy work with the cam cover off (not fun) could seal the direct holes, making sure there is enough indirect 'air supply' for the PCV to pull vapor from the cover. Anything that makes the vapor travel through a labyrinth with drains will lessen oil carryover. In your case an oil catch can will not make any difference in "consumption", only where the oil ultimately goes. The PCV baffle trick is to keep the oil in the engine in the first place.
Google "cadillac forums a river runs through it" for some thoughts on the baffle and fixes.
Because the PCV system is a vacuum bleed into the intake manifold, you must make sure that the designed volume of bleed is maintained - it really doesn't matter quite where the 'air' comes from as long as you don't change the volume - that's factored into the idle and part throttle fuel mixture calculations.
The trick you're looking at is to prevent excessive oil droplet carryover......... regardless of where the excess oil ends up, it's "consumption", and the idea is to lower that, not where you dump the excess oil.
If you don't cause some sort of physical interference with a cam or valve retainer, you can take the 'air' from wherever you want in the cam cover. The PCV keeps the inside of the engine clean by removing moisture and acids - you don't want to defeat that part of the system.
Clean air enters the Northstar from the atmospheric side of the throttlebody to the left (front) cam cover, circulates through the engine, and exits through the PCV valve/orifice in the right (rear) cam cover to the intake manifold, where the polluted air is mixed with fresh air and burned in normal combustion.
EDIT: Holes plugged. If there's adequate air feed area elsewhere in the baffle, fine. If the 3 holes are the total bleed area you MUST equal that somewhere else - away from the offending oil splash.