I have some knowledge on the subject since I have done my own porting. The best and most important thing is not to heat anything and apply to the drum heads. This will only serve to ruin a drumhead and make a mess of things. I suggest that you get a circular compass and painter's masking tape first.
Follow these steps:
1)Tape up the head area that will be cut by applying the tape to the head.
2) Use the compass to trace out the diameter cut size: (4" is the best all round port size in the 4 O'clock position)
you won't loose to much front head resonance.
3) With the head on the drum and tensioned, cut out the traced outline with a single edge razor blade ( make the cut in a vertical motion going around the head. Take you time with this as to not to create jaggered edges.(short passes are better)
4)After cutting out the head portion not needed, sand the inner cut portion of head with 320 grit sand paper to smooth out any imperfections. Be careful not to sand the face of the head. ( Appy tape to the surface to protect this face) Good Luck!!!!!!
Let me know how it turns out tuxido...... firstname.lastname@example.org