I don't dispute what you are saying, my only source for that is what Rob Gorgi told me at WC, I have tested 948 pans on 1275, and vice versa, and know they don't fit, but I have never test the 1098 small journal vs the 948 pan.
I've built one 1098 small journal race engine, it's still out there running too. People just opted for the 10CC engine, due too larger main journals, plus as factory crankshafts elvolved in years, so did the grade of steel they used, they starting using harder grades of steel in the cranks over time. I think it's all about the rpm limits you are going to turn, if you are SCCA racing and wanting to turn 9000 rpms, then a billet crank is the way to go, but if you are racing vintage and turning 7000-7500 rpms then the stock crank properly preparred will give you some good service. Eventually everything breaks under racing stresses, if raced long enough.