Also you mentioned:"Remember that voltage sensitivity drops by 3dB. In other words, an 8Ω JBL 2226H will be 3dB louder than a 16Ω JBL 2226J driven at the same voltage. So you'll want to attenuate the tweeter by that amount to compensate."
Which is good for others to note. However I have 4 ohm, 8 ohm and 16 ohm taps on my MC-240 tube amp and can match the impedance to the appropriate taps for the HF and LF sections which results in no additional loss in efficiency.
Thanks!
Regards, Ron