Hey James
As far as I know, plexiglass and lucite plastic are actually just different brands of acrylic plastic. So they should be virtually identical.
I agree 3 and 4 would look better with more of the reflection, but the owner wanted some closeup shots of the the dog as well. Just out of curiousity, do you find the part reflection on 3 and 4 distracting. I had debated doing these type of shots without any reflection but the owner was very pleased with the reflection so I decided to keep her happy.
Brian