Raptor01,
1. The nose section is mirrored and uses the left (or lower) profile.
2. To make P51BART2 transparent there are two things to try. The first is to use P51BART2_a.bmp that is completely black. If you don't see a P51BART2_a.bmp file, make one by copying P51BART1_a.bmp. The second option is to try using P51BART2_a.txt with the index of the color you want to use as the transparent color. Again, you will have to make your own file -- P51BART2.txt is no longer being honored. I personally went with the first option of using P51BART2_a.bmp when making my p51b skin.
MachNix