Far as Tinfoil Chat, I've recommended it heartily as a project to use and improve. Markus Ottela took what he learned from prior work and our comments at Schneier's blog (esp on data diodes & physical separation) to create a unique, solid design. He's been posting on the blog for feedback for months, we've suggested many risk mitigations (eg polyciphers, continuous transmission), and he's integrated about every one into his system. Most just ignore such things or make excuses: Markus is 1 in a 1,000 in (a) applying what's proven and (b) not letting problems become legacy "features."
So, yeah, I recommend it. Once my personal situation stabilizes, I plan to reimplement it with a tiny TCB on appropriate devices. I'm probably going to do a portable implementation of Send for microcontroller-style systems. Receive will be a Linux box hardened with virtualization or obfuscation security methods. Genode if it's up to it by then. The transport will be a more hardened, cheap box with just that functionality. I'm going to use CHERIBSD, if possible, just to experiment with it. Might replace the raw, serial links with MCU's or FPGA's for higher-speed, one-way I/O. Optical is highly likely (good guess). Eventually, I'm going to put it in an appliance with several, cheap boards so it's all integrated.
On my extensive backlog for now. But, yes, it's one of the best and practically has no TCB. Great design. Can be reused for email, audio, video, and maybe filesharing. Will be my interim framework until my next high-assurance system is ready.