To port or not to port?
On my kits I use for rock/pop, I port the head. It reduces the resonance just a bit, which makes the punch/articulation of the kick stand out more. Sometimes I like the fullness/bigness of the "boom" of the bass drum. In those cases, I won't port, but I *do* use felt strips.
I don't port the bass drum to satisfy soundtechs. That's a foolish thing to do, to compromise on your sound preference for the sake of the miking ability level of the lowest common denominator sound guy. If I see the sound guy/recording engineer standing in front of my unported bass drum, holding a D112 at his side, with his head cocked sideways and a puzzled look on his face, I'll politely tell him how I think my drum is best miked in that situation.
As for cutting the porthole, I've had the most success with the "heating a can" method. It's so simple. The hardest part of the process is carrying the bass drum into the kitchen. The smaller the hole, the better, in my opinion. I've found that a 3" porthole is the size that yields the best results.