Andy:
Good to see the IS progressing. I especially like the second pic, showing the tube on this baby---great vehicle! Your indi tracks look absolutely great, the sag is consistent with actual pics I've seen---so well done here. Also a nice job on the spade,---and you've damaged up the front fenders--good man--this makes this model a little more unique. I like the hand painted number and Russian slogan also.
A couple things for your consideration as you move through your painting/weathering.
Try taking your Russian Green, add some white to it, and LIGHTLY spray the centers of some of the larger "flat" areas, like the top of the front hull above the glacis plate, the turret top and some of the back deck. This will blend nicely with your base coat. Then airbrush on a diluted/thinned dark wash over the whole vehicle - which should tie this all together.
When dry, you might consider drybrushing some high spots, such as the turret rings, edges, etc, with the Russian Armor green, lightened with even a bit more white.
You've got a good build going here Andy, and these suggestions are for your consideration only. This vehicle is solid---good work.
Steve