Wiring limits 5i25/7i76

I'm just getting back into this project after doing other stuff for 6 months. I have a knee mill with steppers. One limit switch on the x and y and up to three on the z if needed.

First question would be how many do I really need on the z? Its a Bridgeport boss. I've seen other guys only use two.

Second would be how do I need to wire them? I have a 24v power supply available. Should they all be wired together? They are NO switches so I guess really that isn't even possible.

Yes same as yours except they are NO...not NC. I originally thought they were NC but i tested them yesterday and they are definitely NO. Didn't test the z axis yet but x and y were. Does that really matter? I was thinking NC would be better.

NC limit switches are preferred because a broken wire
or a wire shorted to ground (with active high inputs like the 7I76 uses)
will cause an immediate fault

That's what I thought. I swear I had checked all this before I out this project on hold so I'm a little confused but the meter doesnt lie.

If I decide to keep them NO for the time being just to get things moving how would I wire them? I can switch them out later.

Ok I just figured out that the switches can be wired either way so I'm good. So I'm guessing they should be separate so I can home all 3 axes at the same time? Also, do I use power off the board or do I supply the power from the 24v supply I have?