Which is a better configuration IYO ?

I have two sets of speaker cables, Nordost Blue Heaven Rev. II Bi-wire and Analysis Plus Silver Ovals. My speaker is a Martin Logan Ascent. For about some time(3 months+), the Logans are just connected by means of the Nordost Bi-wire, and I have a pretty good grasp or memory of how it sounds.
Right now, I connected the AP Silvers to the panels(mid and hi) and the Nordost to the woofers. What I notice is that the sound change. Way different from what I can remember. The highs (as well as the vocals) are still clear but in a different way. The soundstage seems to move backward a few feet(artist vocals and instruments). Doing the reverse(Nordost on the top and AP Silvers on the bottom), the soundstage is back to the original but the bass seems to be extended.
Now my question is this, from what I've read, I got the impression that the Nordost should be connected to the panels, and the AP Silver, (based on the wire construction and design of the two, the AP having a larger gauge), should be better in the lows. It is possible that the Silvers(which I just got recently), needs some break in still. I just want to know your opinion or suggestion if you encounter a similar experienced. Thanks!
I am not sure if Timo is right about not using different wire size, I know you can buy bi-wire from a few different manufactures and get a lighter gauge wire for the tweeter.

My advice however is to consider another wire over the Blue Heaven, at least to try, I had some in my system for over a year and could not get the right sound until I got rid of all of it. It really is thin sounding thru the mids IMO.

Try moving up to a single higher quality wire and not bi wiring, this seems to be a good strategy to improve the sound, often for about the same price as 2 runs of cheaper wire.

hope this helps