OK, I made a decision

I've cut out a new tracing of Schnittquelle Malmedy, with the following alterations:

• keep the total length, including keeping the button placement, cut of the collar, and CF the same
• shorten above the armhole 1.5" (this affects the front and back raglan seams) — this sounds drastic, but the armhole depth seems rather long on this pattern, and mine is rather short
• shorten the top of the sleeve the same amount to match:
• first cut a V-shaped slash from one raglan seam, down to the center grainline at 45 degrees, then square back up to the other raglan seam;
• then overlap the slashed area 1.5", keeping the grainline straight (sounds complicated, but it avoids shortening the shoulder dart). [BTW, I'd considered taking out wedges ending at the tip of the shoulder dart instead, thus keeping the length over the top of the arm the same, but I thought that that length actually should be decreased if anything, since I would ordinarily shorten a set-in sleeve cap, and since the sleeve looked more than long enough overall. Plus, I thought it'd result in a problematic dart shape. It might've been OK if only some of the length was taken out that way, though.]
• shorten total waist length 1"; since the armhole had been raised this actually meant adding 1/2" to the length above the waist
• likewise, those length alterations taken together also meant a relative addition of 1" length below the waist
• when blending the side seams below the waist, I erred on the side of adding more hip room

I may still add some extra width at the side and underarm seams when cutting. Width-wise (except for the sleeves), this is still a 38, and I should wear a "39", more or less.