spinning that big one in the heat of the moment

[VK4TI]

In looking at the cost of either buying a commercialy made rotator locally or importing the same it’s patently obvious to me that anything mechanically able to fulfil my current needs is difficult to justify in the household expense sheet being a major expendature, I can source a worm drive gearbox once the ideal size is determined and motor wattage and torque calculated . I have the skills to mount and water proof the box and motor so seek electrical advice .
Of course one usually needs a manual control box and prefferably something with computer control after all what shack doesn’t have a computer ?( mine has 5)
The question is how to determine requirements in motor and gearbox capacity and can someone suggest a simple control system , I have technical help but simple is best . This will be fitted to a tower under construction in the yard atm some 50cm per side and built to survive an enormous load at tropical storm levels (no not here) raised to a good height , buying a controller might be an option but my budget is currently under surveillance

Looking at ars offers an intersting read but suggest away please
B