For the limit switches it's really up to you how you set them up. On my router I only use 3 optical limits, 2 lower limits for x and y and an upper limit for z. They all double as homing switches. If I had more when I bought it I would have put on both upper and lower limits, but again it's up to; most machines technically don't NEED any of them at all to function properly. (I'm not suggesting you shouldn't hook them up, though

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Sounds like you're on the right track!
Enjoy!
Chris