It's been awhile since I completed a plastic kit and it took me a bit of time to get into the groove again. I made mistakes with each one, which I'll mention below, but overall I'm happy with the results of all three.
I built and painted the Comet and Firefly over the same period this summer. The Cromwell is the Airfix kit which I picked up in 2004 from eBay for about £5.00. It's one of the newer Airfix kits released in 2011, consisting of about 90 parts. I was really impressed with this kit having made a number of the old Airfix kits over the years. It went together very well, with little/no flash on the mouldings and made a very nice model. A bonus for me was the track moulding in one piece plastic rather than the old "rubber band" type. They worked a treat.
I painted the wheels and associated parts of the Cromwell and Firefly as I assembled them. They got a base coat of Vallejo Model Colour (VMC) 924 Russian Uniform. The wheel rims were painted VMC 995 German Grey . I then painted the superstructure with a base coat of VMC 897 Bronze Green. This didn't give the colour I wanted so I repainted with Russian Uniform and applied a wash of VMC 890 Reflective Green or 894 Russian Green (can't remember which), Citadel Badab Black, VMC Glaze Medium and water mixed to the standard skimmed milk consistency. This added a nice depth to the Russian Uniform base. I then highlighted with Russian Uniform mixed with VMC 886 Green Grey to varying degrees and then a final touch of pure Green Grey on some areas.The final step was a dirty wash of Vallejo Game Colour Earth to the wheels and sparingly to the hull.
The Comet was painted in exactly the same way apart from I didn't do any painting on the sprue and only painted the wheels when they were all assembled and stuck to the running gear. The other difference was I went straight to Russian Uniform for the base colour. Machine guns and tool heads were painted VMC Black base with a pencil highlight. Tool handles in some shade of Citadel brown I forget which. The tracks were given a base of some Citadel muddy colour with a drybrush of VGC Boltgun. Then they were washed with a Citadel Devlan Mud/Badab Black mix and then a bit more of a Boltgun drybrush. As a final finish odd areas were very lightly drybrushed with VMC 124 Iraqi Sand which has to be one of my most used/useful colours.
And that's it. I will add some stowage when I get hold of some and possible some markings. I don't really have a firm idea of what to use them for past the usual Normandy/Market-Garden scenarios for the Cromwell and Firefly and an East v West 1946 scenario for the Comet. But before I do that I'll need to get hold of some Brit infantry.