Hey Jason! I haven't ever had any issues with the rear locking mech on my Syborgs. Half the time I don't even bother to feed the buckle through the suit even though the cutout is there. I've noticed not feeding it through the suit kinda lowers the potential for the locking bar to ice up. But to answer your question for real, no it's not necessarily compatible, though a pair of scissors would fix that really quickly as the cuff reinforcement is pretty impressive and stitched with all kinds of rip-stop, so yo...
Hey Joel! This is a pretty burly liner and you'd likely eat up a bunch of volume which may or may not be a good thing depending on what you're looking to do with it. If you are going to go with the Pro Tour though, I would stick with whatever size your boot is and go for the Low Volume. Medium Volume *might* work if you are interested in eating up a bunch of volume though, but I'm suspecting that it might be a bit too tight.
Hey Robbin! The PowerTrack 10 is a closer fit to the Sparkle liner than this one.
Hey Aaron. Yup, you nailed it. Same awesome time tested design as the PDG, only with a new paint scheme and basket system.
Hey James! It's very round and cinches up pretty high on your noggin! Not my first choice of large dual certified helmets! The Kong Kosmos has a nice and low harness that wraps very low on the back of your head and it tops out at 62cm!