When in doubt, Whippet out.
The Whippet is... odd... to say the least. The disc looks weird, feels weird, and flies weird. Everything about this disc screams "weird". But the disc does one thing better than any other disc out there... IT ALWAYS GOES LEFT (RHBH). With that fact in mind, the Whippet becomes an AMAZING utility disc.
The Whippet is hard to find. It was out of production for a while, then they did a limited Star plastic run of the disc. I love Star plastic, so picked one up to try it out as I heard it was good for overhead shots, much like I was using my Firebirds for. I found that to be absolutely true. For Tomahawks and Thumbers, you let this disc go, it quickly does the roll, then flies upside down for a very long way. Outside of the Aerobie Epic, I think this is the best overhead disc I have found, and it has since replaced my 150g Firebird for that role. The disc still does the reliable fade to the direction the flight-plane was pointed on release, but it's a more gentle fade than the Firebird has, meaning this is much better for tunnel-shots and straight approaches.
When thrown sidearm (which feels weird with this disc), it hooks up VERY fast and pulls hard to the right. This is great for hooking around corners, but not for much over a hundred or so feet as you simply cannot get much distance with this disc. RHBH does a similar move to the left and again can be used to navigate corners, though I prefer my Star Roc for this shot. If you intentionally dip your shot, you can make this disc do the signature move I am guessing it was named for... you can make the disc "whip" around an obstacle and pretty much turn 90 degrees or more. This is great for shots where you absolutely need to go around an object, directly to the other side and don't have a clean line.
The Whippet is NOT going to replace my Firebird as my grenade disc. First, these discs are rare and a bit more expensive. I can easily replace my Firebird when I beat the snot out of it. Also, the Whippet when thrown straight up and down, lands much like the Firebird would, but tends to bounce around after the landing, which made it unreliable for sticking the shot. A Firebird just smacks into the ground after a grenade, which is exactly what you want.
As previously mentioned, this disc feels and looks weird. It has almost a double dome. It heavily domes up to around an inch from the rim, then has a second dome that begins from there and continues up to the top. The bottom of the disc also has a unique angle as it pushes out instead fo the normal inward for a mid-range or control driver. It feels very odd to hold as it doesn't align with the normal finger placement. That's okay though as this is not a disc you will use often, and certainly not as a main disc.
The Whippet will likely not come out often due to the limited uses I see for it. I am not going to put this disc in my small bag I carry for casual courses (Par 2/3), but it certainly will be making it into my full-size bag as I can see needing the trick-shots on some of the more complex and larger courses I play.
As for the flight numbers... it's really hard to say. When thrown RHBH, they are probably about correct, but I would probably never throw this disc that way again as this thing just pulls left no matter what you try, then plummets into the ground hard. If thrown with the shots described above though, the numbers change dramatically... my second farthest overhead throw was with this disc in an open field where it flew upside down after a fast barrel-roll and showed almost no fade out to a U-Disc measured 329 feet. Overheads of 250+ feet are relatively easy compared to other PDGA approved discs, and land pretty much right where you want them to.