Hi John!
Really many Ju 88 drawings were made in the last years. I talked to a real expert on the Ju 88 and he told me that not a singel set is really correct, but for him the Kagero drawings are the best.
Many years ago Michael Merker made great drawings of the Ju 88 C and G series. Great reference, but the quality of the printing wasn't good. These drawings were published in 1985.
hope this helps,
Simon