Funny
You should have read the previous posts and reckoned why I replied that to that poster.
Me. I want you to answer my posts instead of just liking them. Seems perfectly clear to me.
You hadn't used the word 'crossover' in this thread until I asked you about 97 times.
Near enough in theory using textbook transient perfect 1st order and the pioneer's polar matching response XO points that will put them in their respective ~ pistonic mid bands well away from the driver's Fs, breakup modes BW, then in theory all that's left is in room level matching, which anyone with good hearing can do to suit, which in theory leaves nothing to measure, though a good plan to have an equalizer/DSP to deal with room acoustics, whatever.
Measurements allow much more design flexibility, accuracy of course, so from a purely technical POV it's 'best', but having done the vast majority of my DIY this pre T/S, affordable electronics way with much success, 'best' for me was folk's VERY positive response(s) to them.
Not sure I follow, though many decades long before the '70s there were some manufacturers with all the necessary test gear to do these measurements and any knowledgeable DIYer can flatten one from Fs to as far as one can measure it with a series notch filter and reactance annulled zobel network.