Spec's don't tell the whole story, but it's a good place to start. According to Eminence's SPL graphs, the Omega 15 runs pretty flat up to 2000Hz, while the PSD2002 comes down to 1600Hz. So, there shouldn't be any holes in between.

Have you performed a frequency sweep to hear if there are any audible holes in that area? If so, try reversing the connection on the tweeter to see if it makes a difference.

BTW, the tweeter's exit throat is 1". The diaphram in the tweeter is 2".

regards,
Gar.