I think that the Seabrook was actually made by the Standard Motor Truck Co, a US manufacturer, The 5-ton Model 88 had a wheelbase of either 9'0" or 9'4", which is a relatively minor difference if you're making a 1:32 scale model (eg, .25 inches). Front tires were 36x6; rear 40x6. These dimensions should help you scale out the other dimensions.
My first attempt to answer you apparently is out there roaming the either somewhere, but certainly is not on this forum! So I'll try again!
It appears that the Seabrook was actually made by the Standard Motor Truck Company of Detroit, Michigan. The five-ton Model 88 (which is nearest in weight to the Seabrook) is listed as having two wheel bases: 9'0" and 9'4"; with front wheels being 36x6 and rear 40x6. Having these measurements should allow you to scale out the rest of the dimensions.
I was starting to wonder whether two different wheelbases were used as some of the photos do show the height as 6' or a bit higher because of personnel standing in front, while scaling of the "standard" 24'-0" photos give a much bigger height.
I'll go through the applicable photos and see if this could be a reason for discrepancies.
One also has to bear in mind the lack of technical knowledge of reporters in "the Old days" as many of them plagiarised other articles written causing errors and approximations become "indisputable facts".
A classic example is Brunton's "Mechanical Traveller" - a locomotive with legs to push it along instead of being driven through the wheels. Several articles appeared on its debut, butthe reporter most probably only saw it from the side and reported that it had one cylinder driving it, as had the original commercial locomotive by Trevithick at Pen-y-Darran. However, if you only have one cylinder, you need a dirty big flywheel to generate the inertia to push the piston back in, which Brunton's machine didn't have.
This means that precise data like yours can be used as the benchmark to check veracity.
