Also, here's a great URL that talks intelligently about slide cornets, which I think is worth reviewing:
https://www.musicforbrass.com/articles/ ... umpet.html
by Chase Sanborn: Lessons Learned from the Slide Trumpet
…“Because of the infinite tuning capacity of the slide, many alternate positions from different harmonic series are available. Each feels and sounds slightly different, and one may work better than another in the context of a line.”
thank you to Saxaphone.org for sharing this incredible image of the #26 Buescher catalogue!