Many years ago I worked a smallish ambulatory center attached to the hospital. I can't remember what our average OR/GI schedule/census was. We had 4 OR's, but only used 3 for surgeries. The 4th was for the odd special procedure. We had 2 endo rooms, but only one GI Dr.
We always had two nurses scheduled for pre-op. One worked 6-2:30 opened the unit, brought back the first patients, the other worked 6:30-3. Another nurse did GI sedation 7:30-4:00. Another nurse, 8-4:30, assessed pre-op patients scheduled for surgery within the next week. She did the Dr. ordered labs, ekg's, vitals, etc.
Two nurses worked phase II recovery. One 8-4:30, the other 10-6:30.
I don't know safe staffing standards for phase II recovery. We weren't supposed to have more than 4 each in Phase II. I do not think a nurse can admit patients and safely recovery Phase II patients at the same per ASPN, (American Society for Perianesthesia Nursing), and AORN, (American Operating Room Nurses) standards. ASPN and AORN are easily Googled and have standards/protocol accredited hospitals need to follow.
We had a medical unit clerk, and a CNA/GI tech who helped out all areas as she had time.
We all rotated through all the departments on a 4 week rotation so we all could help the other area when, if, our one unit slowed down or they really got swamped.