Matching Reds using multiple images

In order to be most helpful we would need to see how you “individually isolated the reds.”  A view of the Layers panels would probably show it very well.

That said, I took your composite image into Lab where the mask was easily made from a copy of the  a  channel. (The Before and After are shown above.)

The PMS color you specified consists of Lab values L42 a66 b34. It was obtained on a duplicate layer of the image and then the mask was added.

As the Curves show, the adjustment to reach those values was very modest. In addition, the comparison of the side-by-side Before and After images show that your attempt to match the reds was well done.

The images are very similar in color.  The variation you see in the reds in your composite image is the result of differences in tone, not color.  

Since the red areas are not flat color,  a modification of the tone in each red area would have to be made individually in parts of the L channel. Often you risk getting a faked result since the images vary in tone level and local contrast. I suggest you use the result you presented here.  Good job.