Bandpass port placement

[G8R151]

Hello all. I'm new to this forum and have a few port questions. I am trying to design a 4th order bandpass box for my 09 altima. I'm installing a JL 12W3v3-4 and a JL 500/1 amp. As for WinISD my sealed space is 1.208 with driver displacement added and ported is 1.875. There recomended port size is (H 4.02 X W 4.02 X L 11.97) Other sites are the same fort port H x W but suggest 5.98 for the Length. Which is correct? And my last question. Does it matter if the port is completley in the box , completely outside the box, or split half inside and half outside? Any advice would be helpfull.