I'm an engineer myself, not a recruiter, but if you want to post an email, I'll take your resume and share it with the right people.
Should I focus on having some/one/few "unique selling propositions" - something I can say I'm expert in? And what would those be?
Anyway back to trying to give you (and other younger folks) some answers.
I've been interviewing candidates for a while. From technical phone interviews, over F2F, and now mostly so called Fit interviews.
And first time I interviewed someone with CS PhD that they have since around the time I was born - I was happy to be paired with another older colleague.
Not that I was scared/intimidated or felt inadequate. I was really worried about candidate getting impression we're a bunch of "teenagers" ;)
So actually on that point I've got nothing for anonOver60 - other than saying to others that instead of being intimidated, you should just be yourself and there is nothing to worry about.
If the candidate is good - being more experienced they'll know how to handle situation in a way that won't make you feel like 2nd class compared to them.
I second the idea of different/customized CV for different roles/positions. In fact each place/position you apply for should be it's own tuned/customized veraion of generic CV..
Put yourself in our shoes, and see how similar the frustration is: Why are you rejecting us? We hire people older than you, we have interesting work, the finances probably work out better... but you reject us.
If at some point you decide to evacuate California, we'll still be around: https://news.ycombinator.com/item?id=17912861
Can you be more specific about what you mean by "engineering services firm"?
Edit - I get it the issue will come up at some stage. But explaining why you changed the dates later in the process is better than not getting an interview.