I think it would be fair to give him 3 games, Norwich, Bristol, Rotherham, and ask for 2 or 3 points. Anything less triggers it.
By the way, there are ways of doing things. The board doesn't have to issue a vote of confidence if they don't want to (even though clubs still do that, see Preston). But you can do a bit of PR. An interview. Some positive video spin. We've had a 2 week break and nothing. No statement, no PR, nada. Either waiting to sack him, or everyone caught in the headlights.
So say Argyle are in the bottom 3 by next Friday after losing to City & Rotherham. You think the club, after taking its time to appoint Foster in the first place & knowing how difficult the championship is, will sack him by next weekend. I think that sounds like what a fan might do, but it doesn’t sound like our owner to me.
Hopefully we win & wont have to find out.