Here's the gist of your problem: these new papers have rather subtle characteristics up in the highlights especially. That's what makes them so appealing. Merely changing the base would change the exact nature of this as well. So you'd only have an approximate test image anyway. Until you fully dry down the real deal, you don't know what you've got. If you're trying to save money and just want to work out a rough dodge/burn protocol, you could do that with any number of cheap VC papers. But eventually, you'd have to try it on the final paper anyway. Even MGIV came out looking quite different between FB and RC. But I don't know why Ilford would want to coat an expensive emulsion on a VC paper to begin with. The market would seem limited. But no harm in you asking. RC papers do rinse fast.