I use Lenox carbide tipped hole saws if the stucco is not too hard. If the stucco is very hard the hole saws will not last long. The also make carbide grit hole saw for hard materials but I haven’t tried one yet. A couple of months ago I saw a 4” hole saw in OSH designed to cut hard materials. I didn’t recognize the brand but I believe it was made in Germany. http://www.lenoxsaw.com/ctholsaw.htm http://www.lenoxsaw.com/grthlsw.htm
I am not completely sure about the stucco, but you might try using a tile cut bit and a roto zip. It sure does work well for that concrete siding stuff- masonite, and I have also made plenty of knock outs for switch and outlets in concrete block the same way.
Diamond core drills. Similar, with carbide tips are just as effective, and will cut an accurate hole through any building material. No need to buy, Tool Hire stores should carry these and the necessary gut-buster drill. 4-5" diameter, no problem. Alan
