i'd be warry about swapping in somthing then immediatly releying on it. as with any complex mod, things are going to go wrong. if you need to rely on somthing rely on the old head that smokes a bit, rather than a new head that isn't designed to be there. with your compression and leak down results, there isn't going to be a mechanical failure for a while... most likely. the head swap should wait until you have a couple of weeks where you can be without your jeep if/when somthing does go wrong. you can usually use a good set of dial calipers to measure the upper most part of the cylender bore, but you will need a different instroment to measure deep into the bore. you can usually do a good visual and see if you have any serious damage. there will be carbon build up on the top of the piston, but if you see one diofferent from the others, let is be suspect. a leaky ring will have the carbon on the sides of the psiton partially removed. you should be able to see the last honing marks. on my 88 isuzu with 190K on it you can still see the orignal honeing marks. if you can see the honing marks and some areas look more warn that others you might have a problem, but the top of the cylender wares faster than the rest so don;t be too alarmed if the marks are week there.