Wayne,
I don't know if you caught my previous posts concerning 4648 use with altec horn drivers (Sam's post really), I mentioned using 288 driver with 16 ohm impeadance and using parallel 15 ohm resistor to equal 8 ohm load to the crossover.
I have 2 separate questions:

1.Would it be easier to configure crossover for 16 ohms, and what values for 18 db/oct (your standard crossover) would you use????? I would need compensation figures also. JBL 4648 = 100 db/watt/8 ohms and 288C per Altec page = 115 db/watt/16 ohms(using 16G diaphram) crossing over at either 500hz, 600hz or 800hz would be fine. I can use parallel resistor to make 8 ohm load and deduct 3 db for the shared load for a result of 112db/watt. This driver has plenty of efficiency to shave and have plenty left, which way is better???

2. I might bi-amp (Rane AC-22 x-over (24db/oct/LR)using 6bq5 SET amp on the 288's (maybe 3 watts on a good day/Knight KN-715 stock) for compensation, can I use resistor in series paralleled with a cap on top end. the bi-amp frequency would be 500 hz. The 288 specified response is 500hz to 16khz. The 311-60 horn I'm using is 1.4" throat with 220hz taper cutoff, and "DOES NOT RING LIKE 511/811" That's the reason I paid good money for the pair of horns/drivers.
Once again, thanks for taking the time for my many "off the wall experiments". I figure since I have so many odd pieces of audio equipment and speakers I would experiment and share my results for those who only want to create/purchase "One system" for themselves and don't have to spend a lots of money to try different ideas.

Wayne, Love the kit ideas!!!!!!!!!!!!!!

Regards, Ron