Happy New Year to you, Alan!
I'm not saying this like I've tried it, but I wonder if it would work. It's not so much a fix for an Alesis crash as it is a replacement option if you decided to go that route.
If you could get ahold of a Strike hi-hat pad, it may work better for you. I use mine as a splash, as I've gone back to my Gen16 hats, but the Strike hi-hat is built pretty much identically to the Pro-X. I've heard the controller is different internally, but as far as the bottom cymbal, it's the same as the Pro-X physically, so the top Strike hat wouldn't have any problem closing over the top of it.
I personally couldn't get the response out of it that I wanted for a hi-hat, but it is certainly better than the top cymbal of the Pro-X. I do know that it triggers well on the DM10, maybe a little better than on the Strike, so it may actually work better for you. I requested the replacement spring for my Strike hat set to see if that solved my problems, and they sent me the whole set. I have the extra pad on my DM10 kit for practice. I'm using it with the RealHat pedal, though.
If I had my DM10 kit at home, I could dig out my Pro-X and try swapping these out for a definite answer, but it's at the practice space. What I can do, though, is take my hi-hat stand to practice with the Pro-X and try it, but it will be a week or so before I'm there. We're not practicing again until next week, before our gig next weekend. If I can get over there before then, I'll try it out sooner and let you know what I find!
Hope this rambling helps!
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Shawn