Since Free Run is disabled in VFR, am pretty sure the answer is no, but hoping someone may have a workaround to suggest. Both cams are set to the same frame rate, if that it makes any difference. Seems a shame this apparently can't be done. Thanks.
In this case, the cameras are shooting slate-averse wildlife and are triggered remotely for stealth -- there's also a lot of starting and stopping and sometimes the cameras aren't both recording every shot, so synched free run timecode would be convenient. Even though I'm the remedial math type, I understand the possible permutations involved with syncing 2 cams with VFR are probably why free run is disabled when using VFR. But that's only a guess as to why.