Taking inspiration from the Big Wheeled Tzar Tank from WW1 Here is the VSF/Steampunk version.
Instead of the spoked wheel, the wheel uses big iron girders for a more solid construction and has a steam boiler that extends in the middle towards the axel on the big wheel (and is connected to it by a bearing shaft.
Two small smokestacks are located behind/below the central turret.
Guns are on the central turret and on the two sponsons.
They can be large contraptions mounted two (or 3) to a base - 4 is very awkward but can be done with overlapping guns... so I would go for less on a base. Or you could treat them as class 5 Land Ironclads
Considering the Russians already have Land Ironclads and contraptions already, I would assign this to another of the European powers. Perhaps Italy (The Italians seem to like crazy machines) or Turkey (may be good for the desert)
The collection allows 4 bases if used as contraptions with 2 to a base, and 8 bases if used as class 5 land ironclads.