I can't help you with that question, sorry. But I can say that I have wondered if you could do a DMaDH experiment to actually try things blindly.
Something like a 100% pale ale malt, mashed and then boiled with some gentle hopping with EKG and Cascade (IBU 25–30 with fairly mild flavour/aroma additions).
At the same time, steeping (or mashing) a, b, c, d, e other malts in separate containers, and boiling to sanitise in the microwave. Then portioning off several brews that work out to be 90% base malt + 10% grain-of-interest in each mini fermenter (2 or 3 L juice bottles, perhaps). Pitch yeast, ferment, bottle and taste side-by-side.
Apologies for a potential derailing post. I just think about this every time a similar question comes up, and I'm constantly googling similar questions and unsatisfied with having to imagine the characteristics described.