I have Walsh 2000's with the omni tweeter for rears and custom front heights with 2000's and omni tweeter as well and they work great.Did you ever take delivery on your 5015s? I am strongly considering making the move to Ohm speakers. I got the idea from MBL, but their omnidirectional speakers are for Kings only, like ~ 200k in price.
BTW - this thread looks nearly dead. Any Ohm owners out there who recently purchased? The customer service of the company is amazing. You can call up and speak directly to the founder, John, and he is a very nice and patient man. Really cool. Anyone have the walsh omni surrounds? Wall mounted?