Query about final approach to land

[GREATINDIAN]

Sir/s, 1st of all before putting my query, let me tell you that I am not at all a pilot or a trainee but a simmer who fly on computer simulator and very much interested in aviation. Though it may be stupid to ask this but still what I am going to ask here is to gain knowledge and expecting that someone will answer my query.

Sir, a plane is on approach to the destination:
1) At what height from the ground level does a pilot should disengage auto-pilot and auto throttle for final approach to perform the landing. In other words what is the safe height to go manual for landing?


2) Taking an example of Toncontin airport (MHTG), the elevation of the runway as we know, is 3300 ft. A plane is on approach to runway 20, whereas the the pilot has to maintain 8000 feet till his final turn to the runway cause of high elevated land and right after passing the hill there is a steep descend to the runway.The distance from the hill to the runway is just 8.5nm


According to the above condition, it means we have to make steep descend to cover 4700 feet to reach the runway just within 8.5nm and at the same time have to maintain the speed for the final touch down.
a) With all the above scenario, is it possible and practical to make a manual descend covering 4700ft for the approach and maintaining the speed same time?
b) What does real world pilot do while making the approach and when they go manual for the final touch down?


This query is only related to going for manual approach. Also kindly don'tmention PARO (VQPR) as Paro approach doesn't have steep descend. We roll the nose up and down while approaching at Paro to make a decent descend even though we are too high above the runway and the concept to approach is completely different..