As a linguist / polyglot, I have a problem with using the syllables "ta" and "da" as articulation models. Physiologically, they are the same, except that "da" adds vibration from the vocal cords, which in euph playing would mean the introductions of multiphonics, which is a whole 'nother can of worms (and I do mean worms). Over the years, has no one been able to come up with a better way to explain the difference between a hard attack and a soft attack?
With regard to tongue position, this may be helpful:
https://www.youtube.com/watch?v=vr8tOa_En7A
David Bjornstad
1923 Conn New Wonder 86I, Bach 6 1/2 AL
2018 Wessex EP100 Dolce, Denis Wick 4ABL
2013 Jinbao JBEP-1111L, Denis Wick 4AM
2015 Jinbao JBBR-1240, Denis Wick clone mouthpiece of unknown designation
Cullman (AL) Community Band (Euph Section Leader)
Brass Band of Huntsville (2nd Bari)