Simple Math--A problem in search of a solution

I got Ander's book from Steve and I have a concern. The three previous artist's before me have each used ONLY ONE SIDE of a sheet or leaf, skipping a page between each artwork.

There are 32 sheets, or leaves left, which is 66 pages. There are NINE artists left, which would be 3 1/2 sheets per person or seven pages.

However, the previous artists have used an average of 5 sheets per person or 10 pages.

If we each continued at that rate, following the pattern established in the book, the seventh artist would not have enough and the 8th and 9th artist would have NONE.

These are the alternatives, as I see it:

• each of the remaining artist use 3 1/2 sheets only (a max of 7 pages, not ten)
  
• OR add a fold -out page or two to your 3.5 sheets (leaves) or 7 pages.
• Or We could continue as started and Anders could send a new book to the 8th person in his rotation.
• Hennie suggests in comment below: use the back sides left by others. Anders, what would you prefer?
  

I need to know how to proceed. I used the page that Steve had prepared for me, but have done no additional work, as I am waiting to know how Anders and the group would like me to proceed.

Here is how I figure the 5 per person: 4 of your own and two 1/2 collaboratives make 5. It works out exactly if you count the pages. 5 pages done on one side = ten pages (5 sheets).

Please let me know how to proceed. Thank you very much. Mary :-D

first draft of an illustration for a kid's book I'm working on (needs work) (I'm putting a print of it in Ander's pocket, as I will not have time to work on it any more before I mail the mole.):