Setting the + knob on the joystick as the power setting for a motor?

[BPtigers]

I am coding an arm with a hook to climb the pyramid. Right now I was able to program the jaguar motor to go up at .5 power with button three on joystick, and go down with button 2 on joystick, at -.5 power. My question is I don't want a constant .5 power when I climb, sometimes if I'm short on time I'd like to be able to climb at 1 or -1 for example, but a button input is either on or off. I was wondering if there's a way to make it so when I click the 3rd button it makes the + button my vertical climb speed, but then when I release the 3rd button the + button doesn't do anything. Also if I where to click the 2nd button and use the + button as my vertical speed down, and when I release the 2nd button the + knob does nothing. If somebody knows how to do this, you'd make my day, thanks. picture is attached with what I have done.