The Whonix documentation should include details about iat-mode for obfs4, for instance explaining that if obfs4 doesn't work one may try to change the default iat-mode=0 to iat-mode=1 or iat-mode=2 (packet size and timing obfuscation).
Would you like to contribute this?
Oh, didn't realize that anyone could contribute to it! Thanks, I added that.
Is it possible to just flip the iat setting or wouldn't this require a bridge that supports it?
In the case of a server with iat-mode=1 while the client has 0, the "obfuscation will only apply in one direction but the connection will still work." https://lists.torproject.org/pipermail/tor-project/2016-November/000776.html I guess the same thing will happen when the client has 1 and the server 0. I tried with some different bridges and the connection worked even do they most likely don't support iat-mode=1 or 2.
It would be better to have the server side also doing the obfuscation, just like some default obfs4 bridges do.