I personally think this was an excellent cook. Not so much because of the end result, but because of the things you learned. You now have a baseline to work from....
First off, grilling lamb is the best way (in my opinion) to serve it. Now you know the boundaries of doneness on that.
Lamb fat contains flavors, much stronger flavors than fat on other things, so realizing that you trimmed it a little close is a good thing. Leaving too much fat on can be overwhelming, so watch that too. Certain cuts, or older lamb have stronger fat. The most important thing is that you liked the flavor. Too many folks try to hide it.
Your seasonings are the same that I use. I do oil the meat before adding them. And I go heavy on garlic, even so far as studding it with slivers of garlic.
Since you are very close to the perfect lamb, I don't want to mention marinades, and I would recommend you stay off those for your next couple of cooks. Work with pulling the natural flavors out and enhancing them with a basic foundation of seasonings.
KCBS - CBJ
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