Also, probably just a typo, but your c19 center driver space says 30, it should be 39.
The boiler currently on 315 is as follows: Smoke box - 42", Boiler (behind smoke box) to cab 172", distance in cab including backhead - 60", total - 274", or 22 2/3 feet long.
For all I can tell, the wheels (not the tires) were the same on all four locos (16, 17, 18, & 19s), but the difference in diameters was due to the tires being different thicknesses. Also, be careful with tire sizes, they varied MUCH year to year, from engine to engine, by wear and shopping. The folios are incorrect in some cases for proper tire size.
Also, I have seen evidence of all classes having flanged center drivers at one point, varying in dates, for classes and individual locos, throughout the span of the D&RG(W).
Casey