Robert is a fairly small guy, relative to you or I- I'm a lot wider and you're a lot taller.
(I don't mean he's a little tiny guy- he's average in size.) I'm pretty sure you'll fit from a width perspective, and you have unlimited headroom- but you might want to ask him about legroom, and about where your head may fall in relation to the wing for visibility reasons. That factor can be altered by the vertical position of the seat though. I recommend calling him. He's a nice guy, very helpful, and spending a buck or 2 on a long distance call is money well spent if it helps with your decision.
Brad
p.s. his full size DrI is one of the coolest things I have ever seen.