Is this going to be a carry gun, or something for range use?
I, like others here, would worry that anything solid inside the firing pin retainer (crosspin) might damage the firing pin over the long run. At the same time, A firing pin is $25 and as long as you aren't going to carry it, it'll be fine and if it breaks, you replace it. It looks like the crosspin might be damaged first anyway.
But what you are asking isn't impossible and if you want to give it a shot, I could probably make something that would work.
If you aren't adverse to spending a little more money for a permanent solution, you might try a dovetail adapter plate and micro red dot. You can use the red dot to rack off of like a giant handle. You'll want to recheck your zero more often than a custom milled slide, but it wouldn't require waiting 8 weeks for a custom slide cut. This is probably the best option, including the handle, because the front of a red dot gives you a nice and big surface to push on.
https://www.egwguns.com/viper-venom-cz-75-75-sp-01-phantom-85-p01-p07-p09-and-pcr-sight-mount-fits-burris-fastfire-and-docterhttps://www.egwguns.com/vortex-razor-cz-75-75-sp-01-phantom-85-p01-p07-p09-and-pcr-sight-mounthttps://www.egwguns.com/trijicon-rmr-sight-mount-for-cz-75-75-sp-01-phantom-85-p01-p07-p09-and-pcrIf you know someone with a mill, they can cut a custom dovetail for these handles, but then we're back to milling the slide.
http://www.fire-4-effect.com/CZ-75-SLIDE-RACKER_p_247.htmlI tried to find a rear sight for the P07/P09 that would be easier to tap for a handle, but no dice. The CGW folks may be your best bet for that kind of adapter. The price is reasonable too, assuming they ever make them.
