Hello Greg, and everyone who plays both trumpet and trombone

Trumpet is my No.1 in the Big band, but I’m starting up a small T-bone career in a church brass band.
I don’t have any major problems playing the T-bone, but it seems that the high register on the trumpet suffer. When practicing in my basement, I try to play trumpet for 10-15 minutes and then shift to the T-bone for another 10-15 minutes – and after that I go back to my trumpet and so on…
Does this recipe seem right for you or do you have any other idea / experience?

Best regards