Other than a couple of blurry and small photos, I have nothing much to go by other than a dimensional drawing in the Seaboard book done by Richard Prince. The dimensions are fine, but the drawing isn't scale and really doesn't look much like the tender in question.
I did find this link:
This tender is very close to the SAL tender.
While the water tank and coal bunker are fairly easy to model, almost nothing can be found on what the front of the tender or the underframe looked like. The link I posted does have a photo of the front end, but it's missing parts and I'm not sure what I'm even looking at or what purpose some of the things I can identify are for.
I'd really like to get the underframe as close as possible. If someone has info they'd like to share I'd be grateful.