I have gone to the French military archives again last WE, and finished uploading what I found here:
https://photos.app.goo.gl/NtDxrFn1oysb8TDZ6 (starting with the updates of the 18th, with the Lorraine APC/supply vehicle/prime mover).
The new stuff doesn't really provide any alternate ideas but they adress the future tanks that France wanted in the springs of 1941 (transitional tanks) and 1942 (future tanks). Their specs are not really unknown for the initiated but you don't find them everywhere so might be nice for you guys. At least it confirms the production variant of AMX-38 was indeed desired for early 1941.
Otherwise some pics of the Lorraine APC, Saint-Chamond WW1 tank during assembly and trials, 1920's prototypes, miscellaneous text on motorization (like command vehicles and the specs for the AMR class of vehicles). And finally, manuals for the FCM 36, Renault UE supply tankette and Renault FT.
The real deal are the 1938-40 discussions on the so-called Fortification Assault Tank, which corresponds to the superheavy projects like the FCM F1. They mostly explain the thinking behind some of their features and evolution (armor, armament, crossing capability), with some drawings of the obstacles they may have to cross in the Siegfried line (here modeled after the Maginot Line).
"All armament and supplies are procured through Czechoslovakian industry. However, the industry cannot produce fast tanks. The value of fast tanks is enormous, which they were fully convinced of when they saw our exercises in 1935. Krejčí asks to give them one battalion of fast BT tanks to reinforce their army. He offered to exchange the tanks for any of their own products."
"My answers: Regarding purchasing BT tanks, I confirmed that the combat abilities of our tanks are high and that I will report to the People's Commissar of Defense upon my return to Moscow and will inform him of the results."
"Proposals: I consider it reasonable to sell the Czechs a battalion of BT tanks in return for technical aid, particularly in the fields of producing tank armour, armour piercing shells, high quality tools, measurement devices, and molds. The Czechs are excellent at this."
https://www.tankarchives.ca/2021/02/export-to-czechoslovakia.html
The more interesting alternate idea I found elsewhere is this. Czechoslovakian imports of BT tanks, and possibly greater CZ-USSR cooperation in the late 30s.