So... given all that, and what I've learned in this thread and researched further... I just pulled the trigger on a MixPre 10 II... wish me luck! Key is that it can clock sync just to LTC, just like the HD-P2 and old MOTU interfaces. Also, while the manual is pretty scant, it looks like you should be able to input TC through the AUX jack and still sync to WC on the BNC. Now... someone stop me from ordering a spidf > WC extractor for $175.
The Zoom F8n/F8 is meant to be clocked synced when paired up with another external source (another F8n/F8).