I had ANOTHER major varnish
SNAFU. I ended up hastily repainting the back end, but the varnish did go on too thick and there's a couple spots here and there where you can see some thickness to it. Oh well. At this point, after having freaked out majorly over it and then had an emergency four hour repainting session, I'm done worrying. It's good enough, but flawed.
For the weathering I made sure to hit the edges of all the deployment ramps with some mud effects. I accidentally got some on the chapter symbols, then I thought about it and realized 'yeah, those would get messy slapping down into the mud' and left them as they ended up.
I also added a quicky alternate roof so it can be hot swapped into being a Rhino. If I get another Whirlwind turret, it can also act as that.