You can start with an Eminence PXB1K6 high-pass crossover or their PXB21K6 two-way. But there's a lot more to it than that. I don't know if you've looked at the schematic or not, but there's a lot more going on than a straight splitter filter. You'll need to add about $30.00 worth of parts to build your woofer and tweeter cable assemblies, and it will probably take a couple hours of your time. If you already have Eminence PXB1K6 or PXB21K6 crossovers, then by all means, make use of them. You'll need to remove the 10uF capacitor from the woofer circuit of the PXB21K6 crossover, or obtain a 1.0mH coil for the woofer circuit if you have a PXB1K6 crossover. In either case, you'll need an additional 6.0mH coil, 0.47uF polypropylene film/foil capacitor and (14) 16 ohm non-polarized 10 watt resistors per speaker. Be sure the coils have very low DC resistance; We use the Erse 5.6mH coil for the large one in the woofer circuit. Finally, pay attention to the connection polarity of the drivers as it is important.
The midhorns are plywood except for the MDF version. We have some horns in stock now, so we can ship immediately. The woods we don't have take about two weeks for delivery.