INSIDE FRONT COVER
Inside front cover: Steve Ditko Mighty Marvel Pin-Up, originally published in Strange Tales #128. Recently reprinted as the cover of the comic that came with the Marvel Legends Doctor Strange action figure. Since Doctor Strange does not have his Cloak of Levitation or Eye of Agamotto in his debut, I felt this image wasn't appropriate for the cover to Strange Tales #110. I used the image from the splash page of the story instead.
INSIDE BACK COVER
Inside back cover: Steve Ditko Marvel Masterwork Pin-Up, originally published in Marvel Collectors Item Classics #10.
I always use the original back cover on the customs.