Depends what you want to measure, if you want to know the tint of the spot then you just shine the flashlight dead on the sensor. If you would want to measure the whole angle profile then you measures at several angle and that tells you how much it varies (see maukka reviews or my thread about LH351D slicing), which is quite important, you might have a nice integrated tint but an absolutely terrible angle profile, as you mentionned somme CREE LEDs are terrible in this aspect, or a 144A might have a terrible egg yolk effect and a nice overall tint.
If you’re measuring a LED bulb, the diffuser averages pretty well already, usually there is very little variation.
Honestly I’m not sure when integrated color measurement is an important metric, I guess for comparing bare LEDs mostly.
Yes as I and Djozz mentioned, the sphere must be color calibrated, even professional ones.