Skully had one installed on Roidzilla, but he had a lot of stuff going on with that bike LOL
Cool head, dual plugs, etc.
Said the compression release made it pretty easy to start.
Couldn't tell you what size would be best for your application, or where to get it installed (any number of builders could probably install it if you sent the cylinder head out).
If it was a simple bolt on mod I'd have them installed in all my quads...no reason to not make things easier on yourself.
Making it easier to kick (and therefore start) might save you a lot of walking if the engine has trouble starting (like a fouled plug or loss of compression).
It's not like you HAVE to use it every time either...