Thanks for the suggestion. I have to slide it forward in my hand a bit to get a grip on the knurled part and then twist with my last two fingers against my palm. That’s a little cumbersome, but it might be workable. It took so long to settle on this light that I hate to go back into the search for another. It’s also good to know that it can be locked out that way and not drain any battery when not in use.
I found last night that there are buying and selling lists in this forum, so I’ll keep an eye out for anyone selling a side switch light in my budget range that I can experiment with without spending much.
Because someone else in the forum was talking about having a thumb problem too, I’ll send him your suggestion.