I can't play at all with anything over 75 flex. Even the Easton Cyclone 70 flex, which is the same as the Ultra Lite but with a thinner grip, was way too stiff for me. Couldn't flex it at all. Balance and shot accuracy was great though.
XN10 Redlite was very light, so much so that I couldn't balance it with a wood blade. A Z-Carbon worked well though. It was whippy enough, but it torqued really bad and my shot accuracy was terrible.
I used a couple other standard shafts, and what I found was that there is a tradeoff between flex and accuracy. Whippy shafts under 80 flex get quick shots off and feel great on the ice, but their accuracy is not good. Stiff shafts over 80 flex making receiving passes easier and accuracy is great, but they're almost impossible for me to load up and shoot in traffic.
What worked well for me was a tapered combo. I'm using the L-2 right now, and the accuracy is as good as the stiff Easton standard shaft and the shots come off quicker than the XN10. I wouldn't waste my time with another standard taper combo unless it was for pond hockey or something.
I'd recommend a Dolomite, Easton Synergy, or Bauer Vapor combo. If you can find the Mission L-2 on clearance, it's a great deal. Between the two shafts you listed, the Z-Bubble is supposed to act more like a tapered shaft, but I picked up the L-2 before I had a chance to try one.