Big Guns or Really Big Guns?

Have been building these guys for a while and finally got them painted last week. I was hoping to play them in-game as Inquisitorial servitors with heavy weapons. Plasma cannons and heavy bolters, respectively. They're not fully painted in these photos, but they are pretty close.

The problem is that now I wonder if the heavy bolter versions are too big and 'robotic' to be considered Toughness 3, single Wound servitors. Deployed across from me I would expect to treat them as T7 W2 3+sv artillery models.

 Compare to the priest, or the 'traditional' metal servitor model off to the right in the first photo. 

As you can see, they don't fit so well on 25mm bases.

So what do you think? I'll have to set them up with an Inquisitor and some bolter-wielding acolytes and see if that makes a difference. I'm pretty proud of them either way, but it wouldn't be too difficult to replace the servo-skulls with gretchin and run them as Kannons with Sootmouf's Waaagh!band.

+++ UPDATE +++

No more wheels. Left the Deff Dread legs alone. The stop-light skull got a mini tread treatment with some ribbed drive belt. The floating hooded skull still hovers nearby the other one, but the gun is mounted on a pair of old single pose Ork legs that got razor-sawed off their donor's torso.

And this is the unit they will be in for BG2016. I had to mix (roughly) 40mm bases with the rest of the squad's 25mms, but hopefully squad coherency will get the message across. I think they at least look less artillery-ish.