Thanks Ron. I do a simple "luminosity mask".
I split the image into RGB slides (greyscale images based on the luminosity or each of the colors). Usually the blue one works best, it's just a hit and miss until you find the one that works.
I place the copied image in a layer above the blown out red (my camera gets very happy when it sees red) then choose the luminosity blend mode. Adjust the visibility of that layer until you get the results you desire.
Occasionally, I'll make a group so I can use a "brightness/contrast" adjustment layer which will let me play with the values before committing to it. In that case, choose the luminosity blend mode for the group and put the adjustment layer inside the group.