The Cal 770 as a Geomatic in a 38mm case would be very hard to resist. To me 40mm is too big for a time-only watch - too much empty space on the dial.
I must say that I sometimes feel frustrated by JLC. I admire their history and their technical prowess, but so often there is some small thing about their watches which just isn't right.
I admit that I will not buy a watch unless I feel it is "perfect". At the moment I have 2 Rolexes (16570 and 114270), the Reverso TT 1931, and the AP15202 which for me are "perfect" watches. I would love to get another JLC but (apart from another Reverso) I can't find an excuse at the moment!