Upgrading Sherman with Calliope set

Heyah,

As mentioned a while back my US armoured forced has been reinforced by T34 Calliope missle launcher. Must say it's been already tested in the field and results are promising:
the turn it moved onto battlefield it blew away Zee German Wirbelwind and spread terror among units around.
Next turn the game was over.
 
Yeah, yeah... It was nothing but the matter of luck but still model looks damn cool and brings lots of fun (mostly for US player) so I hope to include it in army lists frequently.

Sadly I don't have enough space to keep all models I've ever got so instead of purchasing another Sherman decision was made to upgrade model I've already had finished with Warlord's Calliope missle launcher set. While working on the model some pics were taken about both assembling and painting, which hopefully might be useful for fellow hobbyists.

So the operation started with M4 Sherman tank. Model you see below has been painted and sealed with matt varnish, therefore there was no need to undercoat it again before repainting:

Wasn't sure how well airbrushed paint would stick to varnished surface, so just for sure model was treated with very fine sandpaper. Don't think it was necessary but the surface become more porous:

Missle launcher assembly.

T34 set contains like 5 parts which could be assembled and attached with greenstuff and superglue, but since it's gaming model (often transportation) I decided to pin it to the turret. Just to minimalize risk of damage while getting to battlefield.

Assembled - still without glue.
As you can see heavy machine gun and antenna were removed from the turret:

Primed black:

And now something new for me: 

instead of painting model with airbrush and then working on shading, dark areas were painted before base color. Idea was to simply leave these "natural" shadows, making model look more realistic.
Don't care is sounds stupid - it works:

Base color:

Highlight:

Further highlight.

It was actually supposed to be much brighter but nozzle in my airbrush got fucked and is started spitting paints. Visible especially on the turret. 

Decision was made to finish this step before more severe damage is done to the patient:

After paint dried decals were applied: 

And some extra junk on sides and in the back:

Boring part: 

tracks and machine guns were painted silver:

And another new thing for me: oil paints.

I've heared lots about this stuff and recently got few colors to see what's all about. Using oils is way different that standard acrylics but works great on vehicles.

Below - model was shaded with black and brown oil wash:

More washes - reddish brown this time:

And more washing - brown, yellow. Also front / back lights were painted: 

And final details: tools, streaks, mud effect on the tracks.

The model is done: me likey.
It's always good idea to test new things, especially in the hobby. I'll surely use oil paints again on M7 Priest waiting patiently on my desk. I feel sick thinking there're still like 20 infantry models waiting for paintjob...
Anyway - hope you like the final result: