I am sure this is in someones trumpet book but I was dinging around today and wasn't really happy with my double tonguing attack on a major second interval Tu (root) - Ku ( Maj 2) .... so I proceeded to play them in sixtenths ... starting on the low F# ( F#-G#-F#-G# etc for about 6-8 measures) ... then did the same thing a half step higher .... kept moving up a half step after each "rep" until I couldn't. Such a simple exercises was a brutal work out. It also seems pretty effective for finger dexterity and timing between the tongue and fingers.
I have tried similar ones double tonguing different intervals ... not sure if this is over working or a poor use of time .. to me it seems effective..
comments on this or perhaps some exercises you may have made up?