I'm another Volkl nerd - used the C10 for a number of years and added a pair of O10 325g's to my bag two years ago. If you want to lighten up a little from your 5g, the C10 probably wouldn't be too much help there. Mine have lead on the handles for more HL balance. Although they have improved maneuvering like this, they also tip the scales up around 12.8 oz.
I did NOT like the O10 325g when I first sampled it in its stock layout, but when I steadied up the hoop with only a little lead tape, I found a real love connection. The feel and general performance were exactly what I wanted from an alternative to my heavier C10's and I also added some lead to the handles of these O10's for that HL balance that's most familiar for me. I ended up at 12.4 oz. with these.
Last fall, a buddy of mine tried my tuned O10's after sampling some other demos and he loved them, too. He decided to get a pair the O10 295g's for himself and also added just a little lead tape to their hoops. Coming from an older Volkl 8-series V-engine, these have been a very good step for him.
A kid who plays at the club where I work in the summer also tried my O10 - this is a little guy, maybe 11 or 12 years old, and not an especially strong junior. He worked out with my Volkl for an entire afternoon, not just 10 or so minutes, and he was loving it, too. Pretty sure his regular racquet was a rather light Wilson BLX Surge (I think), which I think weighs closer to 10 oz. than 11 oz.
More and more it seems to me that both the O10's and newer Super G 10's have much to offer to quite a wide range of players. If you get an O10 295g along with a pack of lead tape, it shouldn't be hard for you to get pretty close to what you're looking for in a new frame at a great price. If you get some demos, you may also want to have a go with the Super G 10 325g. That one might not need any tuning at all to fit your needs and it will likely weigh in lighter than your ProKennex in its stock form.