I installed the breather vents on my 1.8 and my 2.0 and they never leaked. I used the ones from
CB Performance here for $6.95.
I actually purchased the kit that included a puke box as well. My current motor was a 76 and only had one vent on the passenger's head. The venting all but stopped my oil leaks.
I noticed that one of the posters had installed the nipples going horizontally, which makes routing the hoses a bit easier. However, I chose to mount my "short" valve cover nipples on the top of the valve cover facing upward. This left plenty of room for the hoses and reduced the chance of any leaks. If you want a picture, I can't send one until after August 1st when I return home from vacation.
The hoses from the valve covers were intentionally left a little long (loops upward inside engine compartment) so I can pop the valve covers and move them out of the way for valve adjustments without removing the hose.
My 2 cents,
Mark