Eric Hansmann said:

"FYI, Tangent has released two tank sizes of these GATX type 17 prototypes; 8,000 and 10,000 gallon versions".

Actually Eric, we have released three.  Aside from the two non-insulated tank body versions you mention, we have also released an insulated tank body version:
Info here: https://www.tangentscalemodels.com/general-american-8000-gallon-1917-design-insulated-radial-course-tank-car/
Sold out cars here: https://www.tangentscalemodels.com/product-category/sold-out/sold-out-general-american-1917-design-8000-gallon-insulated-tank-car/

Thank you,

David Lehlbach
Tangent Scale Models