Availability Sentinel / Azalea Campground

I'm considering visiting Kings Canyon the first week of May with an RV.

Azalea campground (Grant Grove) and Sentinel Campground (Cedar grove) seem to be the only ones already open in that particular area. Due to my schedule I may need to arrive on Friday or Saturday at the end of the morning.

What are the chances of finding these (first come, first serve) campgrounds filled upon arrival?

And how would that be for Lodgepole?