Hello Jan , I can't tell you the wall thickness of a Gillott's Tapered tube
without resorting to a Hacksaw. That would ruin my summer! I do recall
Harry Carrington telling me that they experimented with an ovalised Taper
tube - running across the bracket - for extra stiffness. A frame was built.
He wanted to patent this idea but it would have been very costly. Are you
including oversize toptubes? Gillotts built their lugless L'Atlantique with
1 1/8th'' TT.
Mark Stevens Evanton Scotland