Those look great, congrats! Not a bad hatch, overall. The 6 non-hatchers, were they clears? (meaning, infertile, non-starters?)
Helping any out of the shell is always very iffy. I've done it and been right, and done it and been wrong. Theoretically, if a chick isn't strong enough to make it out on it's own, you shouldn't keep it and perpetuate a weakness. But, I know from personal experience that things can and do happen that will keep a chick from hatching properly, that don't have anything to do with genetic weakness. Like if the humidity drops after the shell's pipped, and the chick gets "glued" to a dry shell....but it's always a judgment call, sometimes it'll work out ok, sometimes it won't.
I have a bunch of my eggs hatching at a friends right now, I don't have the time or space to hatch anything right now. I got a batch of meaties from a friend who had too many, (they were undersized birds from a broiler op, so once moved they've grown very quickly, except a handful of runts) need to get those in the freezer before I do anything else. I've had them less than 3 weeks, almost half are ready to butcher now, but I haven't not been feeling well. Soon, though. Then I can start on my breeding trials. Standard Cornish roo over many different hens, and I'm thinking I might keep back a few of these meat hens and see how that works out.