Forget about buying shims
Forget about buying shims----why you ask ????
You can use the old ones and sand them down with something gritty--I started with a diamond knife sharpener---but ended up ending with a very fine stone on my grinder. You can pretty much bet all will need to be thinner.
The advantages ??
1. You won't have to go anywhere to get the ones you need.
2 If you bought new ones--you may find there not just right and have to go back for more--and you can't adjust the clearances exactly the way you want---you can just get close.
3. No cost to you.
4. You can get the clearances exactly what you want---------I always go to the maximum clearance recommendation so as to prolong further valve clearance checkings or adjustments.
I simply measure the clearance---figured out how much thinner a shim I needed----took the old one out---measure it with a caliper and sanded it down to the thickness needed--checking with the caliper---put the shims back in------everything was perfect------perfect is adequate !!!!
The cams don't rub the shims---you are not degrading the metal of the shim.
Take your time---it's an all day job.
If you get frustrated----quit--take a break--come back the next day if necessary.
Drop a part down the motor ??? slit your throat with one of those Rambo knives.
2008 Yamaha WR250R---by far my main bike.
2006 KTM 450EXC
2014 KTM690 Enduro--we'll see how good it is after 70,000 miles.
2013 Husky 650 TR650 Terra