like for example Soclaine Le Tonnant is really just the Rattlesnake with some extra swirly stuff to make it look Friench.
Well, theoretically it was the last duty of the captured Rattlesnake.
It was captured by British and after few years sold to French and used by a corsair corvette and renamed "Le Tonnant".
That is theoretically the reason of those two twins models.
But I cannot demonstrate it, since I have found no real evidences.
Keep in mind that the original construction plans of the "Le Tonnant" were made by Vincenzo Lusci, which was the "Backbone" of the pioneer period of the wood kit manufacturers in Italy, more than 50 years ago.
It was their main source of construction plans.
So, since it was a "pioneer period" I cannot be sure of the level of research done for making some of the construction plans.
Some of those model originated by those construction plans are still in their catalogues.