A quick question to think about: the William Tell excerpt is marked at hn=108. I don't believe I've ever heard a recording at that tempo.
Check out the William Tell recordings on TromboneExcerpts.org and you'll find they're all doing the run in the high 90's.
Here's the rub. Normally we should listen to recordings to guide us in our excerpt preparation. But what if the recordings let us off the hook??? Do you really walk into an audition and play it at 96 or 100?
Is that being accurate or is it copping out?
(Actually, I'd really like some famous guy to say,
"Oh you should really play that at 96"
thus saving me hours of toil.)