From my perhaps trivial useless archives. Not verified, have no idea where I found it.

Vitus 888 set
which was called "type Grand Tourisme" are as follows,
The three main tubes are .8mm,
the head tube is 1.0 mm
the seat stays and chain stays are 1.0 mm
the steerer is 1.6mm to a butt of 2.5 mm
the fork blades are, 1.2 mm if they are 28x19mm or
1.2 tapering to 1.5mm if 29x16mm.
The steel is classified by Ateliers De La Rive as E36-3 steel