This is how I learned. Nothing else worked for me. Wobble means not enough spin which comes from arm moving faster than the wrist. Slow down the arm. The wrist has to move faster than the arm to get rid of the wobble.
I can get a lot of spin but still wobble. I think it is the rotation of my wrist on an uneven plane what is causing the problem.
It can also be that you are using discs with too high of a speed rating for your arm. I can forehand a Katana Blizzard Champion for 400' and it starts with a little wobble, but I can also throw a DX Leopard for 370' and it's a clean rip with no wobble. It just tells me I have more than enough arm for a Leopard and not enough for a Katana. I can get an AvengerSS out 440' though, no wobble. So my distance is achieved with a slower disc than the disc actually rated for 440', due to my ability or lack of ability to properly throw the discs according to their speed rating. High altitude also causes issues, at sea level I think I could throw just about anything, but 6,700' really makes it a challenge to forehand faster discs IMHO.
First post... feel free to ignore me too...