What centre channel are you using?

This will sound like heresy to most, but I gave up on the center channel years ago. I like a lot of older movies, and got tired of having the sound only come from the center speaker. Now everything in mono is coming from the right/left and sounds great to me. And the talking is easier to understand. Just my opinion, but it's not written in stone that a center channel must be used. Try it for yourself.

No center only really works ok if 1) your processor supports a phantom center and 2) if your sitting pretty much directly centered.  Otherwise your guests are getting the short end of the audio stick...

back to the op:. I just "side graded" my old Martin Logan Ascents/Logos center to a trio of Gallo Strada 2's and a pair of Gallo TR-3D subs and couldn't be happier.  (A request was made of me, to reduce the speaker footprint from the ML monoliths to something smaller) The Logos was "kinda" timbre "close" to the Ascents, but nothing is better then three perfectly matched fronts.  Awesome.

I'm trying a KEF LS50 for center with KEF Reference 107/2s front LR and LS50s side and rear surrounds.  A round of pink noise reveals the LS50s match the big 107/2s well, and the sound for music and HT is superb.

i am a fan of full range speakers for centers. I use Klipsch KG5.5 for my center speakers behind an AT screen. 

My 2/4/16 post needs an update.  Although pink noise suggested the KEF LS50 would be a good match with the KEF Reference 107/2s, I was always aware of the LS50 as a separate speaker.  The KEF R600C blends seamlessly with the 107/2s.  I do use four LS50s as surrounds.