My washes are usually 80-20 or 90-10, depending on what I am trying to do. I do recommend applying a glosscote and letting that dry for 24 hours before applying the wash. The glossy finish helps the wash move around the seams and panel lines of a vehicle.
As for T-55 dioramas, do a search on Google for T-55's or for Operation Iraqi Freedom and you should be able to find plenty of ideas. I have lost count of the number of photos that I have saved. HTH.
Erik
"Don't fruit the beer."
Newest model buys:
More than I care to think about. It's time for a support group.