Well, look like you won't make long tour every day, so yes the guardian should be good.
You should take a hour or so and read some review on the barons/duke, guardian's and the other a/t binding. They all have their pros/cons.
For the center mount, I don't get it, does it gonna effect you? But if i'm not mistake, aren't the Magic J the bigger brother of JJ? If so they are meant to be mount at recommended cause they are 5 dimmensionnal ski ( I don't know how to say that ha )
For the boot, buy something that fit, but if you change your boots, you have to make a choice between tech boot and tech binding or boot like the salomon quest that can fit in the two kind of binding.
But since you're startinf touring you should buy something like the quest or the other boot along those line, the new quest backcountry or whatever it's called ( the blue one i think ) looks great.
I'm tired and can'T help you more, I'll give another read tomorrow, I might tell some shit that are not right.
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