Hi, I'm 6' 2" and race in a MX150R (Original Race Spec Exocet).
My seat is set as low back and as far back as it can fit in the chassis (Cobra Monaco Pro) as it's a bit wider than some others (I'm a big guy !).
Even with my Helmet on I fit under the Roll Bar..
It's Still advisable to put Roll Cage Foam on the Bars mind you.
Seat wise is a personal and financial choice! It depends if you want to be well supported on Track, or just a Road Car or go the full hog and get a race licence and come racing ?
We race around the country in the 750MC Sports Specials Championship and fellow Mev Owners (or prospective customers) are always welcome, we can sometimes provide Free Tickets to Race Meetings with advance notice (subject to availability)..