I stick to Star Thunderbirds. I've found them almost universally more overstable than Champ (not necessarily right out of the box, but definitely over the long run--I've let my Champ Thunderbird thrower friends throw my Stars and they confirm). They are very straight at high speeds, with reliable fade at the end. They get straighter as they wear in, even flip up a bit at high speed, but don't really turn much. In my bag today, I have one that is Firebird overstable (with a bit more distance and glide) and one that is quite HSS, but a little straighter on the finish. I use them into headwinds, or when I need something that will not turn or drift right and will finish left, to varying degree. Mostly throwing them on more open lines or where I am ranging distance with hyzer. The two in my bag are probably 9/5/0/3 and 9/5/-.25/2
I also stick to Star (Sirius) OLFs. In particular, the 1.1/zippertops marked "SOF". They're flat and the plastic (2006) seasons much more quickly than modern star. They start pretty straight with some fade but they season very differently from Thunderbirds, developing high speed turn before they start losing their fade. Even thrashed ones retain some late fade. I use these mostly in trees or on flip-up or turning lines. I'll even roll them. Right now, there are 4 SOLFs in my bag. One is a recent 1.5 run, modern Star plastic, which I actually think of more grouped with my Thunderbirds, then 3 SOFs. By numbers, they are probably 9/5/-.5/2.5, 9/4/-.5/2, 9/4/-1/1.5 and 9/4/-1.5/1. (Aside: I actually just a got a few of brand new GlowOLFs, but haven't thrown one yet. They are going to be HOGS--SUPER high wing and I suspect they will fly like Firebirds.)
Basically, I just added Thunderbirds 2 years ago after YEARS of throwing OLFs, because I wanted something that I could MASH on, even in some wind, and trust not to flip over, finishing either straight-ish or left. And I wanted it to feel as similar in my hand to my OLFs as possible--both discs use the same Firebird 1.9cm bottom wing (OLF has a Wraith top while Thunderbird has its own unique top).