Would you please elaborate further on your 3rd paragraph (“complicates things a bit further, because the crossover will introduce some loss at mid/hi frequencies but not at low frequencies”), didn’t get what you mean. Thanks.
Hi Norm,
I'm envisioning that resistors which may be present in the speaker's crossover, and/or to a much lesser degree the dc resistances of its inductors, may be significant contributors to the relative balance of lows and mid/hi's.
Since you have bypassed the low frequency section of the speaker's crossover, but not the mid/hi section, you may therefore be raising the sensitivity of the speaker to low frequencies relative to its sensitivity to mid/hi frequencies. If so, the level matching you would have to accomplish with the active crossover would have to reflect that difference, in addition to the difference in amplifier gains.
Regards,
-- Al