So just like when external HR is used the native optical HR is displaced, when tempe is used it will displace native watch temperature?
I guess only HRV data is stored as developer fields, would have been nice if tempe was separate and merged later in Connect, etc.
There's that neat datafield that stores external HR as an extra set while maintaining native HR so I guess the same could be done with tempe but of course there is only two datafields available on all Garmin watches (except rare 735)
Garmin really should look into allowing four datafields, if it's a performance issue maybe there are code profilers that could probably squeeze out more cpu cycles, look at how javascript and css engines in browsers have been radically optimized over the past decade.