This is an awesome project - it looks amazing, particularly the lit explosions.
Re the weathering, you seem to have got it about right now, with rust streaks on the hull, but the superstructure fairly clean. Basically, they'd clean and repaint anything they could reach/get at*, but things they couldn't (sides of the hull or high up bits) would suffer the longer a voyage went on and the worse the conditions. It was worse on WWII ships than modern ones because they didn't have the anti-corrosion and paint technologies we have nowadays, and many of them were painted in a rush even by the standards of the day. If you look at pics of the RN ships coming back from the Falklands, you can see that
Hermes (near WWII standard) looks far scruffier than
Invincible (1970s standard).
*DK Brown reported that when they re-built the Leanders in the 1970s, they found as many as 80 coats of paint, weighing up to 45 tons, on some of them.