Millenium Bypass - Mosfet Question?

[mattpocket]

Hi,

In this layout: http://aronnelson.com/gallery/TheBigMan-Layouts/mb

There are several layouts for the millenium bypass. I knew there were two kinds of bypass, millenium one and millenium two. Which is best to use?

My main question is, what is the difference between the N and P type, and in which situation do I use each one. Is it something to do with the polarity of the circuit. For negative ground I use the N type and for positive I would use the P type?

Thanks

Matt

PS. If you lot are getting pissed off by my barrage of questions, sorry, I am spending my days cramming all the info about pedal building into my tiny brain!