I have a base-model Witness steel-frame 4.5" barrel, so I don't know if this is relevant or if the Hunter has a different feed ramp. I bought 100 lead 155 gr SWC and trial packs (about 20 each) of 140 and 200 gr lead TCFP. The SWC did not feed very reliably in my first batch of about 25 rounds. I have not yet gone back to play with the seating to see if I can fix that. The TCFP all fed 100%; not surprising since that is the most popular profile for the 10 mm.
I got the 140s and 200s from Badman Bullets. I don't think that alloy is what would be considered "hard" by most people. If loaded to max velocities, I'd bet they would mushroom some if you hit an animal, but that's just a guess. Some day I will shoot one into water jugs. The 140s I loaded VERY light for plinking with a light recoil spring. The 200s were a standard load in the middle of the load range (don't remember the charge offhand.) Light leading with all of these: not zero but not enough to require cleaning before you finish a box of ammo.
Most TCFP have a small meplat, but Beartooth Bullets sell one that has a different shape and is presumably more destructive. Maybe you could call them and ask if it works in a Hunter. They have a conflict of interest in answering that question, of course, but some companies do place honesty over sales. I don't know if they are one of them.
The DA/SA trigger on my gun was OK but not great when new. After a couple hundred rounds and a few hundred dry-fires, it is still a little stiff but seems better. I would hope the Hunter's SAO would be much better. People like the SAO in the Elite Match, which is much cheaper than the Hunter. I don't know if they are the same trigger mechanism.
I assume you've shaken hands with both of these guns? The Witness has a rather big grip. I like it, but I have fairly big hands. I find the reach to the slide release to be a little long if I don't have bare hands.
If you do not get enough info here, you might want to try a forum that has a higher percentage of Witness shooters:
http://www.czfirearms.us/index.php?board=27.0