white on white

I did a shoot recently of two pharmacists, seperately. The client wanted the shots on a white background for an ad in a newspaper and the subjects would be wearing a white lab coat, cringe.
I decided to try and make the background a bit whiter than the lab coat so i could clean it up and at least have an edge to work with on the coats. I used one light (shoot thru umbrella) on the subjects, and one flash pointed at a 45 to the background to make the area behind their heads white. I was in a very small office so the wall to the right of the subject provided fill.
The people were great, shots looked fine, and the individual shots were easy to clean up.
I thought i would see how difficult it was to strip them together and that proved a bit more challenging but not too much.
I extended the left of the canvas on the ladys photo and drug the man s shot in. I created a mask on the top layer (man) and filled it with black to hide all, i needed to see the ladys arm as i wanted it in the front. I then made a rough selection of what i wanted of the man to show and filled it with white. I chose my paint brush and painted in the rest of him (close to the lady).
By the way, i used the dodge tool set to highlights with an opacity of about 15 to make the backgrounds white in the single photos.
I also had the ladys head pointed down a bit which resulted in her neck buckling. I used the liquify filter to tuck it up into place.