It's been my experience that continued use of thinning shears make the coat get more cottony and difficult to deal with
I use an 8 1/2 clipper blade, it's the only thing I'll touch a spaniel with (cockers or springers) It is short but it is very natural looking and doesn't seem to alter the coat with continued use.
You can "skim" in down the sides of his legs to get that side stuff off , then lighten up your touch with the clippers when you get to where you want to leave the feathering in, and use a light touch on the clippers to blend.
Yikes!!! Just googled coat king!
Oh, no! If you want to hand strip I would use a McClellan or Mars stripping knife along with hand plucking.
How old is he? Do you have pics?