Hi Davey,
thanks for the curved ball
Its not so much a deviation from the design I have in mind (ie in tube placement), but a substitution of 'larger' materials (bigger OD tube of comparable strength to 'book square'). Think of just replacing the top rails
(sorry don't have book to hand to refer to part numbers) with bigger OD tube.
Re TT's point regarding aesthetics, I'm considering alternative body treatment that may leave top rails etc exposed ( see
http://www.mevltd.co.uk/missilegallery.html for an example) hence thinking of all this in first place...