I have now figured out how to fit Mr. P with a long-sleeved shirt (I had done the short sleeve version at Easter). You wouldn't believe how many places you have to fold, angle, cut, splice, and dart a pattern to fit a little guy who has broad shoulders, small rib cage, slender body, and long arms.
Store-bought shirts don't fit well at all, which is why I started this shirt-madness in the first place. (I had sworn I'd never make long sleeved shirts again!) Patterns are just as bad as store-bought tops, if not worse. One can sort of understand why everybody puts their kids in tee shirts!
I am working with "Sm-Med-Lg" patterns. They are WAY too wide in the body--beginning right under the arms, too narrow in the shoulders, WAY too short in the length and sleeves, and about 4-inches too wide in the waist/hips. So I am pretty much using the shoulder width of a size large, the body width of size small (or less, depending on the pattern), adding an inch to the sleeve length of size large, and adding 1-3 inches to the length of a size large--all for what the stores call a size 7.
(As I understand it, "small" should correspond to 7-8, medium 9-10, and large 11-12--and I am having to add length to size 12????? And take away width from a size 7???? He is NOT disproportioned at all--in fact he will have an enviable physique I think!)
You can't just "do" what I described above; you have to fold, dart, taper, splice, tape, etc., to get in those wide shoulders above the narrow body. Then you have to remember the effect of all this on the armhole depth and curve. You have to start from scratch with each new pattern--which is why I will work mostly from one short-sleeve and one long-sleeve pattern, vary materials, and add trim pieces (as in Western), etc., to achieve different looks.