"Lift" (vertical takeoff) would be the aircraft weight + drag at the desired rate of ascent. The aircraft will accelerate upwards until thrust (vertically) = weight + drag.
Drag coefficient can be modelled from flat plate or other appropriate flat shape
(top view of the aircraft would be best), but keep in mind the ascent rate will be relatively
slow and the majority of engine power will be used to overcome weight.
The power required curve, with an adequate safety margin for downdraft, would be
at maximum for liftoff and ascent, reducing as aircraft begins to move forward and the wing begins to generate lift. This power/thrust reduction could be from over the weight of the aircraft at lift off to less than 25% of it in level flight.
Interestingly, all aircraft do this transitioning from climb to level flight as they reduce power and "level off", again using the more efficient wing for lift instead of their prop. VTOL aircraft simply do not use their wings at all for lift off.
Power/thrust requirements considered, a STOL may be a happy compromise.