Thanks, BookCat. Yes, I found the options for managing pauses etc., but these (in my software) are global, and really I would want to alter the effect just in particular places. You can create text with relevant adjustments, but that's not appropriate while I'm still editing. If I was going to try and set up audio files for others I'd definitely do something like that - with enough time and effort I believe a very good result would be possible, but would be a lot of work.
I think "said" became verboten (just one 't'

) largely through exaggeration - as has happened with adverbs, italics, exclamation marks and telling. You don't find many successful books without examples showing that these are all quite acceptable - in the right place, and in tasteful moderation.
The exaggeration came about through articles wanting to attract attention: being moderate about something is boring; being extreme makes people look.
The reason for wanting to advise authors to be more cautious about their use of attributions (and adverbs and italics and so on) came about through serious abuse. Some authors, even some that have since become quite famous, have sometimes been highly inventive in all these areas and such abuse drags the reader out of the story to stare at the words - and this is not a good thing.
But alternative verbs for speech are sometimes useful. Adverbs that do, indeed, prop up some dialogue can be more efficient than rewriting dialogue to show the intent. For all that people insist that a story should show, not tell, the simple truth is that this is "story telling", in most cases a good story will be a mix of showing and telling.
All of it is always about getting the balance right - and right for your story, and the particular place in the story, because the effects required vary with the situation and narrative style.
But no one wants to read about moderation and balance. They want the hard and fast rules for success, so adverbs become words to hate, "said" becomes the only permissible verb for speech, exclamation marks become the butt of jokes ... and writing becomes that much more boring.