Hi Kevin,
Looking good so far. On your weathering try using some alternative colours on the wheel mud to break it up a bit and don't forget to weather behine the wheels on the hull proper.
The tracks on the Cromwell were steel and although you've muddied then up the black plastic is still showing through. Try painting them hymborl matt 70 first and go from there.
If you want some mud try using ordinary garden soil add water and dab it on where you want it. You can add different pigments to different parts to get a more realistic effect.
Road wheels on the ranks were rubber and would have had a greyish look to them.
Your getting the idea of it, but take a bit more time with you painting. Think about a real vehicle, the mud will be around the tracks and sides, the further up the vehicle you go the cleaner it will be. There will be greese and light dust on the top surfaces, oil stains around the fuel caps etc.
Athough you've said you haven't painted the wheels of the Sherman because it doesn't seem worth it, they will show through.
These look lijke nice little kits and if you take you time you can use them to experiment with different painting techniques.
Try making a water wash of slightly darker green and running it all over the tank first. Let it dry for a couple of hours and see the effect. There are lots of good articles on site about painting techniques and I don't claim for a minute to be any kind of expert but your builds look good so it is worth taking a bit of time to paint and weather them as best you can.
Good luck and I hope this helps a little.
Cheers
Al
