No doubt, as Richard said, this is the #1 solution to your problem, given our individual perceptions of sound and what we are able to hear in a noisy environment, depending on our ears, etc. No one can answer this fully except yourself, I believe. My own aged hearing is compromised in noisy environments, and thankfully I don’t have to play in them, so I cannot offer my solutions in the same situation.
However, I think the key of the whistle (and thus timbre) has a lot to do with what we are able to hear in such conditions, depending on the whistle design (and materials sometimes). For example, I once had a Cillian O’Briain Low Eb that was so nimble (responsive) and clean toned, that it seemed to outperform any other key in his line for a low whistle, though I didn’t have an E, but all others. Bore ratio to length might have been optimum, I don’t know, but possibly the low E might have had a similar effect, of which is one of the keys you mentioned you are interested. Maurice Reviol made most of Cillian’s low whistles from that period when he worked for him in Ireland, and since he took over the same design and low whistle business afterwards, (with Cillian’s blessings), you might check out one of Maurice’s low E’s, if he is still making them, though my Eb was amazing. Yeah, like so many others, it is one of the one’s that got away from me in a moment of madness, and moving on to other whistles and/or in need of cash at the time.
Any whistle can be made to favor a strong low end, or an easier high end when the whistlemaker knows how, but often it is luck of the draw when you buy, unless you request the maker or seller ot pick one for you, especially if they have more than one example at hand, or make it for you specifically with your requirements in mind. Aluminum seems to be the one to carry the favor in materials for being heard over brass instruments for whistles, but there are variables, such as delrin heads that may complicate or complement, depending on the end result on specific whistles and makers designs that are available.
Unfortunately for you, your amplified results will be different from many others here who don’t use electronics to enhance or alter the live performances, so you again are the one who has the last word or solution, though I hope you do get some other specific replies that help more in that regard.
Good luck-hope you find your grail!