Phase Plug Dims ?

[valveitude]

Greetings all,

I have a pair of Paradigm Titan drivers to play with, and would like to fit some phase plugs. I realize this isn't a full range driver, but figured the guys in this forum have the most experience with them (the plugs that is).

First my assumptions (please correct me):

1) The OD of the plug should be sized so that the VC just clears it.

2) The length of the non-tapered portion should be such that at max excursion the eddge of the VC lines up to the start of the taper.

Assuming the above is correct, what should the length of the tapered portion be? What are the effects of the various shaped plugs? The majority of the plugs I've seen are of the "nose cone" variety, but have seen some pretty wild looking profiles, and am curious as to there effect.

Any input would be mucho appreciated.

Thanx,
Casey