Interesting setup! Could I ask if you have tested the RD75's to see how far they can go upwards and downwards? I see that you got some advise from ThomasW to cross relatively high to the HDS182's, but there are quite a few reports of good results down below 300. Any experience with this?

Also, have you tried EQing the RD75's to get them (closer to) flat up to 20k?

700/speaker is not bad BTW - I have a feeling I am looking at the wrong side of 2k per speaker. Still, should be worth it!