Thanks Jean and Bob! All of this is learning experience for me, so any input, even based on personal opinion and privately-held value, is worth something to me.
For my part, I can only judge the craftsmanship by my limited experience, having never held more genuine tsubas in my hand than there are fingers on that hand <does quick count>, "yup, six." At this early stage, I would hardly know tagane if it hit me in the face; all I can say for magnification is that the lines themselves have crisp sharp edges, and include intentionally-placed details that I wouldn't otherwise notice (the tiny dimpled texturing on the shishi's paw pads, for example, totally escaped me until I looked at them under a looking-glass, just now).
Assuming the crack is a true issue of some degree that will forever bar it from the upper shelves of a collection, and on Bob's suggestion that doing so isn't completely idiotic, I think I'll put this back in the Mounting Option A category, and wait until the fuchi-kashira arrive to decide once and for all.
I'm just trying to be careful here; I'm cognizant of the limitations of the blade I'm working with, and trying to make sure that what I build is honest for the period, circumstances, and economics of it's original owner. I don't want to be the kid that couldn't afford a real sports car, so he buys a Honda Civic and then tacks on a bunch of high-priced aftermarket crap.