My primary concern is to avoid being flagged in dragnet surveillance by either my communications or by my Tor usage They both address 'blockability' while you need to address 'detectability', or as meek's threat model docs put it: 'observability'. You have to understand that both transports have a different threat model than yours. Is this analysis correct? I can't find any information online re the relative safety of these transports in these terms, only a generic recommendation everywhere that 'obfs4 is best.' I would prefer obfs4 if possible, only because it is much, much faster, but thought I should check. I'm aware that this might be a complete misunderstanding of these transports :).

The recommended obfs4 transport would be less safe, since connections are going to IP addresses of bridges, which may be known to the surveillance agencies. Meek might be safest, since the connections are going to innocuous IP addresses associated with Google App Engine / Azure / Amazon. I am not so concerned about targeted surveillance - if it reaches that point I will be harassed anyway. My primary concern is to avoid being flagged in dragnet surveillance by either my communications or by my Tor usage.

The government is known to be trying to track Tor usage. My threat model: I am engaged in entirely legal, non-violent communications, but I am concerned about potential harassment from my nation state as I am an organiser.

I am trying to figure out the implications of using the different types of Tor bridges - such as meek, obfs4, etc.

Obfs4 with tor app