B20Wannabe

Trying to figure out the best way to vent the block of my B20. I have the bungs off the front of the valve cover but in reading several articles (yeah thats right I searched) it says the back of the block is needed as well. So my question being would it be functional to run four lines (two from the valve cover and two off the back of the block to a catch can??? Also there was someone on here awhile back selling catch cans with 4 inlets and I can't seem to find the post anywhere. Anyone know??? Thanks for any and all input.Happy Holidays!!!