John,
Nice pictures, I like the Vintage Chrono, and also the JLC.
I think the flat case back of the JLC (I have a Reverso Grand Taille) is what makes it appear bigger on the wrist. I tried a Vintage King Size on recently and the curve of the case back and lugs made it sit nicely on my wrist.
Thanks for posting (another GP for the wish list)
Regards
Martyn