I was contemplating getting rid of the vertical carrier strip, but was unsure how flimsy the panel would be. The panels I make usually go thru pick & place machines. If your assembling the first lot by hand, I would try the panel without the carrier strip and see how rigid the panel is.
I've also contemplated v-scoring the tabs. That would give you a very clean break. Next time I do a panel, I'll ask the board house what they think about that.
I've only dealt with Circuit Express at arms length (customer dealt with them). They only do prototype or small quantities. They don't do production runs unless your production run is small. I've done cost comparisons with Circuit Express and US Circuit - US Circuit was slightly cheaper for a 1 week turn. That might have been due to the relationship we have with US Circuit (they know what to expect from us). The quality of Circuit Express is very good. I've seen sample boards from their roving salesman and a few of my customer's boards. Circuit Express appears to have very good pre-flight personnel. They caught a few questionable things on my boards that knowledgable folks would catch.