those who say bowl geometry is more than significantly influential for taste have rocks in their head.
Actually, we have argued this point, toe to toe for a long time now. And, with all of my evidence presented that there is a difference between smoking a large bowl, verses smoking a small bowl, you still continue to demand proof, while offering none yourself.
Over many threads, I have offered literary evidence of this topic being of discussion for decades, maybe even centuries. Also, a thorough breakdown of why the tastes are different between bowl sizes, with images of bowl geometry.
Then there is the whole argument that cigars are sold in different ring sizes, because some people prefer the small diameters of the same leaf, and others prefer the larger ring sizes. Why would this be any different for pipes?
What it breaks down to is that a taller more narrow bowl gives you less smoke per sip, with less leaf actually combusting per sip, and less mass of heated leaf giving off essential oils. Whereas, a larger pipe gives more smoke, with a more robust taste for the exact opposite reason as per using a taller more narrow bowl.
Now, all you have offered is... nothing to the argument. To me it would seem that someone who smokes these two pipes with the same tobacco and reports no difference at all in the taste is the one with rocks in his brains... or at least is pitiable in their lack of being able to discern tastes.
And, as to proving... all I have to say is that I merely offer an explanation for what should be an obvious difference. And, I would encourage people to get a few pipes with extremely different chamber sizes, and try it for yourself.