Just my $0.02 to add to all the advice you've already been given.
First, for terms, google them. The Innova website has a glossary of terms as do other sites, and will explain overstable, understable, and other such terms.
Second, in your initial post, you did not say what you were throwing 200 feet, then later said you had the Beast and Valkyrie. That is IMHO the highest speed driver (speed is the first of those four numbers you see on many discs) you need right now. The Leopard would probably be a very nice addition to your bag and you might well throw it most often as you develop your form and technique.
You can look for a "Roc3" instead of a "Roc", they are similar (IMHO, the "VRoc" is not similar, but I digress). But I use a Panther myself and really love it, so I'll endorse the Panther as your mid.
If you like the Rhyno and are successful putting with it, by all means keep doing so. If it's not working well for you, the Wizard, the Judge and the Aviar are all good putters and come in a huge variety of plastics. Do you like soft or hard plastic or in between? Get what feels good to you and go practice with that putter.
Last, but not least, and this will be contrary to what some others here believe, but IMHO you should develop ONE throwing technique. Learn how to bring the disc across your chest properly, get the "snap" to spin the disk, get the release, and repeat that throwing motion until you do it in your sleep. Don't contort yourself trying to throw one disc three different ways.
Have fun!