In article , Barry
Klein wrote:

How should we have found the correct mixture setting
for power-off final approach, when the turbo is basically adding no
boost and we are at high density altitude?

My best advice is to go to www.avweb.com and read all of John Deakin's
articles on engine operation. These are gems of wisdom that every
flight instructor should have in their kit.

Somewhere I read an article that related that many aircraft
carburetors/injectors are not properly set for idle.