with early production Martin Logan Sequel II we find that the bass speaker is best matched with the 4 ohm tap, while the electrostatic panel is best controlled by the 2 ohm tap. On later production Sequels we use the 4 ohm connection to both drivers.
I'm pretty certain that the result of doing that (what they describe for the early version Sequel II) would be boosting the output to the bass driver by 3db, relative to the output to the electrostatic panel. Yes, that conceivably could result in subjectively pleasing sound with speaker/room combinations that are poorly balanced, but it is certainly not an ideal way to obtain accurate sound. Basically, it amounts to using the output transformer as a shelving tone control.
I'm basing that on the assumption that the transformer taps are designed to provide the same impedance to the plate circuits of the output tubes regardless of whether an 8 ohm speaker is connected to the 8 ohm tap, or a 4 ohm speaker is connected to the 4 ohm tap, or a 2 ohm speaker is connected to the 2 ohm tap (if there is one). And on the fact that the speaker load impedance is reflected in the output tube plate circuit in proportion to the square of the turns ratio of the transformer tap that is used.
Similarly, the original poster's proposed configuration would result in a 3db boost to the bass driver(s), relative to the highs. A non-starter in my book, as I had indicated, at least if the speaker/room combination is reasonably well balanced.