I just recently bought a star sidewinder, but it doesn't hold it's normal left to right flight path (RHBH) as well as I had expected. Is this because the star plastic is a bit more overstable than champion or dx?
Yes, at first. Star plastic tends to be more overstable, but becomes less stable than the champ stuff. One other tid bit. Months ago Dave D. from Innova was on this site and talked about the diff plastics. Needless to say. All my "high speed" discs are Star plastic (Teerex, Destroyer and Orc) and the "slow speed" discs are in Champ. (Sidewinder)
If you search "star plastic" or "night shift Orc" you can view his resposes to the diff plastics and their character diff.
Buy them in lighter weights. Lighter weights take some of the stability out of discs. My Star Sidewinder is 164g. It will stay turned if you put a bit of anhyzer on it. If you throw it with a small amount of hyzer it will cut the sweetest S-line you have ever seen.
I've noticed that as well, my Star Max and Star Xcal were near impossible to flip over and now i'm doing it constantly with backhand and sidearm. My champion plastic is still just as difficult to turnover and I've had the discs the same amount of time.