well, you could give it a shot and hope for the best. :-)
using the impedance from the measurement on the spec page will get you much closer than using the nominal impedance.
around 5khz, the impedance on the woofer is about 16 ohms or so.
an "L-pad" that you could use to adjust the tweeter level would make it easier to get things matched up.
you didn't mention anything about baffle step correction, so you may end up with speakers with really weak bass.
or, you could get a copy of the loudspeaker design cookbook by dickason as that would be a good start to learning about speaker building...