#49, 50(1st & 2nd Prints), 52, and 71 all have Carl covers and #104 will also have a Carl cover when it gets released.
#3, 11, 34, 56, 57, 77, 82, 84, 94 and 100(Philips Cover) all have Carl on the cover.
I'd also get #2 & 83 signed they don't have Carl Covers but #2 is his 1st Appearance and #83 is the Issue that Carl gets shoot in the face.
#2, 3, & 11 are getting kind of expensive but #34, 49, both 50's, 52, 56,.57, 71, 77, 82, 83, 84, 94, and 104(When it gets released) are all still reasonably priced.
If I was getting these signed I'd definitely go with #3, 49, 50(1st + 2nd Prints), 52, 71, 83, and 104 because they all have great looking covers.