Mitch
Your Corsair looks brilliant but "a lot of fillers and paint, hence the extra weight" will not make it fly any better indeed it actually makes it more difficult.
I would seriously put the Corsair to one side for the moment and get plenty of RC experience flying something else preferably lighter. slower flying and most important easily repairable.
Certainly join a club and get some proper RC tuition.
If you try to learn by yourself you
will crash many times. Do you really want to risk your pride and joy?
Even if someone else has shown that your Corsair can fly that is absolutely no proof that you will be able to!