I hate to say it but now that you got the right yellow shade you should give it some dirt to make it feel realistic unless for some reason you want a factory-fresh look. With a model that large you should start adding more details as well. Drill the barrels out, dirty the plates (mud around feet whatever, bit of black wash in recesses), add some battle damage (little cannon shell strikes/etc.). You should also consider getting a few shades of metallic colors on the massive blocks of silver, the single color blocks on multiple parts may be 'realistic' but they aren't that flattering on a model and especially with trim work and a large scale unless you're doing high detail such as faux reflection NMM work to give the components definition. So for instance the metal piece holding the chainsword arm on, paint each piece different metals, like make one of the arm rings a rust/bronze and give it a tiny burnt gold highlight, paint the cylinder with the 4 cut-outs body panel color, etc. The great thing is subtle things (like painting a lot of the 'rivets' a silver color to make them look worn/removed/maintained) can add a ton of detail to the model without a lot of effort because of the size.
