"Horn of Plenty" Three Way X-Over HELP

[rlabomb]

I have recently completed the build of my attempt at a speaker that produces the full audible range. I loosely based the design around U.S. Patent # 2,866,513 awarded to Stan White in 1958. The patent was filed in 1952 and utilizes a "folded" horn design that does away with any angles in the horn and keeps the air movement consistent. In the original design, the horn terminates at the front of the cabinet. I moved the exit to the back but mirrored the curved sections of the horn.
I have built two versions of this speaker. The first is 20" W x 15" D x 28" H. It uses a Morel MW-266 8" and a Morel dome tweeter. The horn behind the 8" is about 15 feet long and about 40 cu. ft. The second speaker I call the "Horn of Plenty". The dimensions are 36" W x 24" D x 58" H. The 15" driver is a vintage CTS unit and the 8" mid / bass is a Trio unit from the late sixties. I used a Hi-Vi ribbon tweeter. The horn behind the 15" is about 160 cu. ft.
I would like some help in designing a crossover. I am currently using a down and dirty vintage Sylvania crossover from a console. I know the crossover points are in the wrong place but it sounds pretty cool anyway. Some of the bass notes it produces I haven't even heard at a live show. I use a 15 watt tube amp with them and regularly shake the suspended ceiling. Anyway, if I use high quality caps and inductors, will a very simple 1st order crossover with 2 or 3 caps and 2 inductors be the way to go. All the drivers measure 8 ohms on my multimeter and I am looking for about 500Hz for the 8 inch and 2500Hz for the tweeter. Thanks in advance.

--Rlabomb