Long time Leopold FC660C user here. I've owned 4 of them over time, setup at both home and office. Topre 45g silenced being my preference.
I've really, really wanted a 2.4GHz wireless variant since forever, which will probably never be made.
As such, I've bought a Royal Kludge RK84, as it's 2.4GHz, a similar form factor, and hot-swappable. I'm using Boba U4 Silents in it at the moment, but the pronounced hump to create the tactility makes even the 62g weight feel too heavy. I have Drop Halo Clears on the way but I suspect they'll also feel too heavy. Finally, I have some Bobagum 62g linear silents on the way, which might feel about the right weight, but I'm anticipating that they'll feel mushy compared to Topre (MX Silent Red feel very mushy compared to Topre).
If anyone has ever tried an MX compatible switch that is close enough to Topre 45g to mean I can move onto a more modern board with USB-C and 2.4GHz wireless, I'd love to hear about it.