Good and bad news, I worry about the presence of those dirty air inlets....
Valves are pretty straightforward, do you have a Shop Manual???
One thing I did was zip-tie the cam chain to the cam sprockets before removing the cam chain tensioner.
Be sure and put the lock pin ( a long 6mm bolt works fine ) in the crankshaft through the cases when the two marks on the camshafts are pointing toward each other ( and aligned with the head's gasket surface ) before removing the cams and you'll be golden.
There is plenty of room to remove one cam at a time to remove the valve buckets. I'd cup a hand underneath the bucket as soon as it comes free ( I used a magnet on a stick to remove them ) in case the shim drops out.
All mine were stuck to the bottom of the bucket, but they are installed in a recess on top of the valve spring retainer.
Be sure and follow the loosening and tightening procedures and use a torque wrench ( a topic beaten to death lately in these pages !! )...
I got a 9.48mm Hot Cams shim kit from Amazon for about $60, 3 of each size. Of course I needed FOUR of one, but was able to re-use one of the shims I removed to get the valve in-range. I prefer to set as close to the higher tolerance as possible. Tappy == Happy...
Good luck!