Sony if I remember right from doing mine during the winter of 15/16. Definitely bring home your caliper. The marking could be rubbed off. The intakes are to be between .10 and .15. In my mind .12/.13 is perfect. But .15 is certainly OK. Loose is better than tight. And .10 is on the tight side but is really OK too, but it is at the tightest it should be. So it may or may not tighten a little more before the next inspection. You have to decide if you are OK with that and how long until your next inspection will be done. Yes the same philosophy with the exhausts .15 to .20.
You are thinking right. The way to go is only remove the shims that need changing. You may find when you measure them with your caliper you can swap them around. I was able to swap mine around and only had to buy 1 shim. To prevent having to pull the cams and worry about getting them timed right and getting the ladder torqued correctly I used the Rocket Scientist valve depressor tool. You make it yourself. Also another tool you make yourself is a slightly ground down screwdriver. With Rocket Scientists tool I could depress the valve and get to the shims by myself. With the ground down screw driver I needed my son to help me.