Hey Paul, I've found some interesting information about Japanese seaplane tenders.
http://www.combinedfleet.com/Chitose_t.htm
If you scroll down to the timeline of early June, you will see that the IJN tender "Chitose" , carried 16 seaplane fighters, probably F1M2 Pete's, and 4 Scout Planes, probably Jake's. Later on in July 1942 they are listed as having a compliment carried on board of 14 Pete's and 5 Jakes, with two of each type carried in addition as reserve aircraft.
From another website and the old Tamiya 1/50 scale F1M2 Pete model instructions, (from my stash) they list the tail codes as starting with "YI".
The instructions also called for the Pete's to be a solid overall gray if operated from the Chitose.
Here's a rather comprehensive list of planes and the colors taken from the Tamiya "Pete" instructions: These instructions list the tail codes for various float planes as operated by the IJN. These include planes from battleships, and other types of surface vessels too. The list includes the tail codes for the planes and the overall colors, such as gray, or green over gray.
Here's a picture of the camouflage patterns used on the Pete's.
and finally the decal sheet from the Tamiya 1/50 scale "Type O" Pete.
The decals have the tail codes and numbers in various shades, white, yellow and red, depending on what vessel the plane was operated from.
Hope this helps...
PS, if I get things finished with the other 3 Midway Group builds in time, I may just start a "Pete".
Up until today I was not aware that they were used at Midway. It looks like they may have shot down or possibly damaged a B-17... using a F1M2 "Pete" from a seaplane tender.
So if someone is looking for a unique subject for the Midway Group Build, the "Pete" biplane would be another good choice...