I think probably its been near 26 home cat to newly arrived cat introductions here at my home. All but 2 were successful. After I had the newly arrived cat worked up for any of the usual parasites and obvious infections we opened the closed isolation room. Had a homemade door frame with chicken wire placed within the existing door frame. Here the face to face introductions began. At first with my supervision with a water spray bottle in hand. Day or two later I could safely walk away and let the home cats satisfy their curiosity about the new kid in the iso room. The wire screen door frame would be kept in place anywhere from 5 days to 2-3 weeks. Odd thing is that when the wire frame was removed the home cats would mostly ignore the new kid and would be more intent on investigating in great detail the contents of the iso room. Meanwhile he new kid would be mostly free to explore far and wide their new home.
Photo of my homemade door frame here: <img src="">