Patching and Plastering - Blending new knockdown texture with old

I've been doing rather extensive remodeling in my house (built in the late 1950's), including things like removing closet doors, then applying a drywall patch over the old opening. I have drywall patches all over the house ranging from a few square inches to entire walls. All the taping and sanding is done, and looks great. The next step is apply a knockdown texture to try to match with the existing walls. I'm worried about having a mismatch between my new, crisp knockdown texture finish, and the old, more softened edges of the existing knockdown (which I'm sure has been painted many times in the past) when I have a drywall repair in the middle of the wall. I don't have a preference as to whether it all looks old, or all looks new...just so the differences are minimized. What do you guys do to get a good match? I don't see this discussed much in any books I've read. Here's my ideas. Tell me what you think, or give some better tips:

1) Skim coat the old knockdown with joint compound, prime, then apply knockdown so that the entire wall looks like new.

2) Sand the old knockdown to smooth, prime, then apply knockdown so the entire wall looks smooth.

3) Apply the knockdown finish on the patched areas, then paint with many coats to soften the edges of the new knockdown to make it look like the old.

Anyone?

I can tell you are an intelligent guy and have covered the bases. If you pick 3, just remember that when you paint the new area to not overlap the old, because if you need to put 6 coats of paint on the patch area to mimick the 6 coats on the old that have "softened" it, you don't want to be rolling over the old again and building it up to 12 coats. Know what I mean?

thebeave, I hope you'll come back to tell me what worked for you because I'll be facing the same problem soon. I don't think my old texture is as old as yours, though.

I don't think I'd want to do #2, either. That would be a lot of sanding. Yuck.

I think you can do this. I've done it and it worked.
Put some texture on the patch. Match it as closely as you easily can then respray and knockdown the whole wall. You will have nice new texture and the whole wall or room or whatever will look the same. The texture might not look exactly like the old original but will look good and will be uniform. It might have just a tad more relief to it than it has now. I like that look.

thebeave, I hope you'll come back to tell me what worked for you because I'll be facing the same problem soon. I don't think my old texture is as old as yours, though.

I don't think I'd want to do #2, either. That would be a lot of sanding. Yuck.

I'm done, and for the most part, it all looks good. In my hallway I had about half old wall, and half brand new drywall. I ended up skim coating over the old knockdown texture with joint compound, then lightly sanded with a 300 grit sanding sponge after it dried to get it smooth. Then I primed both the old and new drywall with a water based primer. Then I applied new knockdown texture everywhere using a little $20 plastic hand pump Homax texture pump gun and a broad knife. After it dried, I sanded lightly the texture with the same sanding sponge, to remove the teeny specks (boogers), and to soften the edges a bit. Then I primed the whole thing again. Haven't yet applied the top coat, but it looks like a brand new hallway now, and there is no mismatch at all!

In my bedrooms, I didn't bother skim coating the old texture (too much area to cover!), so I have old and new knockdown side by side. It's actually pretty acceptable, and I don't think most people would really notice it unless you got a few inches away and knew where to look. I used flat paint, and the natural and artificial lighting is such that the difference isn't that noticeable, especially after a coat of primer and two top coats.

Overall, I'm pretty happy with the results. My little Homax hand pump gun works like a charm, and gave me a good muscle workout to boot. I bought a HUGE sack of dry texture compound for about $10. That was a much better deal than the premixed stuff Homax sells in a plastic bottle. I tried to use a Homax pneumatic texture spray gun I bought for about $50, but couldn't get it to do anything except dribble goo everywhere, so I gave up and went to the manual method.