twin stick movement Galak-Z style

Hey guys. I am currently trying to implement twin stick character movement Galak-Z style. Gamepad Right Trigger to move forward, Left Trigger to move backward, Left thumbstick to rotate and right shoulder to increase the speed AND (thats important) also move forward if neither of the triggers is pressed. Trust me, you want that in the hussle of a combat. So, to implement that without the right shoulder movement would have been really easy and straightforward(first pic). but when you get to this one, you strart simultaneously getting multiple movement inputs, which tend to get in each others way. I would suggest to disable input from the rest of the buttons, while one of them is pressed. But got a ****** mess as a result of trying to do it(second pic).
If you have any ideas or suggestion it would be really great. Thanks in advance :slight_smile:
Pardon my English.