I've pondered it a bit and I'm not sure either way yet, I'll see how they look once they're finished. It won't be too much trouble to paint it something else if it doesn't work (or turn the pink to melon!)
I've been also musing on further additions... after seeing some other work I think MkIII armour will be fine for the Sunder, it might just be the helmets that fit less. Or perhaps that's purely down to how heavily MkIV they are - might assemble a couple MkIII Marines for some melon and white.
I'm also giving more thought to vehicular additions. While a Rhino or two are first on the list it'd be worth expanding to other things, especially stuff I can't do elsewhere. Over time I've grown fonder of the Heldrake (again, some great paint jobs and conversions I've seen) so I'm wondering about adding one. I've heard they're not bad in 8th too, and it'll be good to have non-Marine things to break up the power armoured hordes.