I'm relatively new to reverse searing (last year or so), but when I do, I employ it with ribeyes with good success. If you have temperature probes, you shouldn't need the ambient temp one - just the meat probe one. Typically my ribeyes are at least 16oz (1.5 inches thick). The thickness impacts how long you should sear them. Season your ribeyes generously at least an hour in advance and let them come up to room temperature.
I typically use one full canister of regular charcoal briquettes, and set up for indirect cooking. Once I get the coals arranged, I place my grill grate on top with the lid on, vents fully open (top and bottom). Insert the temperature probe into the thickest part of the largest ribeye and use that as your temp guide. Put steaks on the side without coals, close the lid again with the top vent over the steaks and wait for the temperature of the steak to come up to 100 degrees (during this time, you don't need to flip it or mess with it at all). Once the temp reaches 100, open the lid and take the probe out (this is where the reverse sear comes into play). Spin the grate with the steaks still on the grate so that they now sit above the coals directly. Put the lid on and wait one minute. After one minute, flip the steaks to the other side of the grate and spin the grate again so the steaks are over the coals directly once again. Put the lid on and wait one minute. Note: The searing part moves quicker than you expect when doing this for the first time, so be ready with a timer, tongs, a platter and gloves to spin the grate. For me, one minute of searing per side is plenty. I'll take the steaks off, cover them with foil to rest for 5 minutes. If you like medium rare, this amount of rest should be perfect to get them to 130 degrees. If you like medium, let them rest for a total of 10 minutes. For thinner steaks, I wouldn't sear for more than 20-30 seconds per side (or you could take the steaks off at 90 degrees and sear for one minute per side - not sure if that would work, but it's probably worth a try). The reason for the grate spinning is that you'll effectively be searing your steaks on a "cold" grate which results in a greater overall sear on the meat and not so much from the grill grate bars themselves (minimizes the sear marks from the grate).
One other note on searing, some like to prepare more hot coals while the steaks are cooking indirectly to add to the existing hot coals once the steaks are reaching 100 degrees. They dump those new coals on top of the existing coals for a super hot zone. I personally think that's unnecessary, but it definitely creates a thorough sear!
I hope this helps! Good luck!