MHS V1 & V2 and newbie questions

I am new to the site and wanted to know if MHS V1 & V2 parts are interchangeable or their own separate systems. Also I was thinking of doing a Neopixel blade, but I heard mixed things about them for dueling. Like you can or cannot dual with this type of blade. I know what blade length I would like, but the width I am unsure of. What would be your recommended width? My final question is the Neopixal 11 pin, is that for up to 4 strips or just 2? I am planing for an animated effect blade style, kind of like an unstable blade look. Thanks to anyone who can answer my questions, and yes I did see the stickies for newbies and read them.

V1 and V2 are different sizes, however there are adapters available in the store that can be used to combine the two.