Here is my post on my helm storage compartment/glove box solution. If you scroll through you will also see ways some have tweaked the idea to fit them better.
Helm Storage Compartment Solution
Bennington also just came out with a small glove box type add on option. You could inquire with your dealer about it.
Not sure what you mean here: is the front porpoising at high speed (bouncing up and down) or are you talking motor/prop cavitation in the back when under speed? Have you adjusted trim, and if so, does this take care of it?
I’d think either adjusting trim OR motor mount height, or both would rectify the issue depending on which issue it is.