If you end up having to replace valve shims your life will be much easier with one of these
Also buy a couple of cheap 19mm open end wrenches and cut them in half to make "shorties". You may have to open them up a bit until they fit the forged "nuts" on the cams that are used to hold/turn them. Also be very mindful of the procedure for removing the cam ladder or you can ruin the head. Not trying to scare you off, but shim replacement isn't for the faint of heart. Getting the cams back in time is no joke.