I got my mits on the HB Tanker, & noting the comments above, I submit my tuppeny ha'porth to the discussion.
I haven't seen any size comparisons with the eponymously genteelly elderly Italeri Closed Cab Water Tanker, currently on re-release with D-Day Anniversary Flash on the box.
So I've compared them & put lots of pics on my Club website here EastMids Model Club
In my Shadow.
& Can't hide!
Dimensions in mm;
Height: HB:23.4mm IT:24.55mm
Waistline at moulding: HB:21.7mm IT:23.08mm
Width at bottom of door: HB:23.4mm IT:24.55mm
Width: HB:34.74mm IT:34.94mm
Length HB:37.61mm IT:35.03mm
(over side of bonnet)
Width: HB:16.26mm IT:16.09mm
Length HB:71.35mm IT:68.38mm
Width: HB:40.18mm IT:39.22mm
Length HB:16.64mm IT:16.73mm
Dia: HB:26.32mm IT:25.05mm
IT tyres are thought to be undersize anyway?
Width at base: HB:44.38mm IT:41.88mm
Width at waist: HB:44.02mm IT:43.24mm
Height not measured, as not possible to get consistent measure points, see pic.
Screens: HB screen in 2 1/2's IT in 1 'v' shape.
Height of front windscreen: HB:10.82mm IT:09.12mm
1/2 width of split-screen: HB:17.55mm IT:16.09mm
Rear Screen: HB rear screen in brass PE mesh.
Width: HB:17.99mm IT:19.02mm
Height: HB:07.98mm IT:07.01mm
Conclusion: The HobbyBoss cab & Doors look 'squished' **WHEN COMPARED** to the Italeri.
I'm not planning to build this soon, in any variation, but Dimensionally, it shouldn't be too hard to drop-in the Italeri cab over the HB Chassis without too much effort.
THE HB kit does have a very comprehensive engine though...
The HB sprue does have a fair few gaps in the gate layout & one part left on (B7, 2nd row down, left) does look awfully like the soft-top screen?
Still worth the effort?