How much rudder input does a Cessna 172 require during the take off roll?
With several hundred hours logged on multiple variants of the 172, I would give the relative answer of ‘not much’.  In my experience a C-172 tracks pretty straight with only slight right rudder pressure needed on the ground roll.  It is much less than what is required for a C-182, 206, 210 or other high performance single engine Cessnas and much less that a lot of tailwheel airplanes I’ve flown.

It seems like in a 172 when you are brakes off and rolling, I usually rest my heels on the cockpit floor and apply a slight pressure on the base of the right rudder pedal with the ball of my right foot.  It is necessary as the plane will waltz to the left during the takeoff roll if you don’t.  But the force applied and the deflection of the right rudder pedal is light and limited, if you do it right.

A recommendation might be to send a developer down to a local flight school operating the C-172 and arrange to practice takeoffs and landings with a CFI so they can get an empirical sense for what rudder input is needed on a takeoff roll.