Here is one of the best color references out there.
www.ipmsstockholm.org/helpdesk.asp
Other advice: Do not count on restored aircraft for historical accuracy when used as a reference
for color.
As for WWII aircraft, while it is in the eye of the beholder, I don't think any modern airplane is near as beautiful as a Spitfire, Mustang, or a Super Connie.
Good choice with the B-17. The kit has been around in one form or another for more years than I care to remember but, it's an easy build with decently fitting parts. The only problem area I remember is a step between the upper and lower wing halves where the nacelles join the leading edge but, it's easy to deal with. If you want to go crazy with detail, there are plenty of aftermarket sets for both interior and exterior. Just depends on how much money you want to spend. Eduard is a GREAT source of AM parts for your kit.
Good luck
Ray