Bridalveil Campground Advice

Hi everyone,
I have a permit for Friday starting at Mono Meadow, and was going to try to snag a camp spot at Bridalveil CG Thursday morning to avoid having to travel up from the backpackers camp in the valley.
I know it's first come first served, but wasn't sure how early one would need to get there to get a spot.
Back up plan would be to have a 6-pack of beer in hand and see if we could squat in the corner of someone's site for a night.
I appreciate any help people have.

Get there around the time people will be leaving.

I am happy to report that there were plenty of campsites available at Bridalveil Creek Campground when we showed up around 11:00 am on 8/29. Maybe the lack of potable water scared people away, or maybe it was just par for the course up there. Either way, it was nice being able to camp so close to our trail head as opposed to staying in the Valley and needing to drive up to Mono Meadow.

Did the campground fill up later in the day?

When we left about 9 AM on 8/30, there were still spots available according to the sign at the front. We passed by again on 9/3 around 2:00 and saw the campsite available sign. We did a 5 day loop out of Mono Meadow, so I wasn't able to see if it filled during the holiday weekend.