Hooray for Kimberley, Mark and other replies above.
Speaking as someone who, these days, definitely falls within the "older male" category, I'm acutely aware that when you have accumulated decades of experience, you tend to get grumpy if a person appears to be offering a solution that's just looking for a problem, (in the older males' view).Then, as a "pocket", these males will fulfill your self-fulfilling prophecy that they are grumpy and unco-operative for as long as you continue to try to convince them. It's like arguing with an auditor - It's like wrestling with a pig in s**t - the auditor (older males in this case), actually enjoy the experience.
The secret (it shouldn't be one) is failing to at least show enough respect to ask, before assuming you have something good and worthwhile to offer. Once they are convinced you are a twat (rightly or wrongly), the journey back is long and perhaps impossible.
Suggestion: At the first glimpse of grey hair and beer bellies (particularly if they are tradies, technicians, engineers, scientists, even senior operators), go into listening mode. But be genuine, these guys have been problem-solving for donkey's years, mostly with no thanks, so they are independent, self-motivated, dogmatic, determined, skeptical and bloody-minded. These are skills that got them through. Now, some upstart is waving a new procedure in their faces. Or god forbid, "safety culture".
Example: Speak as yourself, don't use "We" as in "We are from Head Office, and we are here to help". The Weasel-Word Radar will spot that one. Maybe say: "I'm interested in these machines. They can do a lot of harm, as I'm sure you know. Please tell me how you make sure they are de-energised before you work on them".
My bet is you will get an answer. Don't now jump in with your pet project. Show interest, ask more questions, build a picture. I'm not going to develop this too far, but you get the idea. At some point, you will be able to say something like "I'm glad you guys are aware of the risk and you are doing bla bla, but there's one or two concerns I have and here they are. How can we fine tune a bit?" Do not quote rules and regulations to a group. Save that for the one or two stubborn buggers and do it sparingly, one-on-one.
It's not a magic wand, but this is the way to get these "experts" onside. You will probably get better than you wanted, in a fraction of the time, with little or no kicking and screaming.
And imagine a "pocket of older males" putting their very partisan support behind your end result...