Repairing a hole in old plaster wall (1940's house)
I'm looking for some help in the best way to repair a hole that's ~3" x 7". The house was built in 1945, and the walls are plaster, but not with wood lathe. The wall appears to be made of 3 layers: right under the paint is a very thin (I'll describe below how I'm thinking of approaching the repair, but please tell me if something won't work well, or if I'm WAY off base with this idea. As I'm sure will be obvious, I don't know a ton about home repairs, but so far I've managed with other, smaller holes/repairs around the house. (No problems yet!)
I was hoping to use the drywall repair clips to attach a support to the existing wall--I don't know if they'll fit over such a thick wall though. So if that won't work, then I'll use a couple of small pieces of wood and screw/glue these as supports to the inside of the wall. Then, I'll place a piece of drywall (or sheetrock?) as the base support and screw/glue that to the wood supports. Then use patching plaster on top of that, anticipating that I'll need a few layers of it to completely fill in and reach the same level as the rest of the wall.
At any point in this, do I need to use that self-adhesive tape to cover the gap between the patch and the existing wall? I'm always afraid to use the tape, because i expect that it will make my patch into a more visible raised area after I apply enough patching plaster to cover the texture of the tape.
If anyone has any suggestions for this repair, I'd really appreciate the input. I've read lots about drywall repair (and I really envy those with drywall now)... but tips for plaster walls are a bit more elusive. I'd like to do a decent job with this repair though--the last thing I want is to have to redo it a year from now.