A couple times over the years I’ve needed a radiator hose for a non stock application, I was able to find auto parts stores that actually had a paper catalog, with diagrams & dimensions, and picked out something that would work. The key of course was finding someone with that actual catalog, and not just entering an application in the computer. Those paper catalogs do often still exist, but you might end up ordering one from the manufacturer, if you don’t have an auto parts store that still has stuff like that. If you have a large NAPA nearby it’s possible they might.