Patterns with optional set-in sleeves

Generally, if you're making a set-in sleeve, you want more armhole/-scye depth than you would on a sleeveless version of the same thing.

Very often, home-sewing patterns with sleeved and sleeveless views do not take this into account. I've just cut (out-of-print) New Look 6387, which is no exception. In this situation, it's usually a good idea to raise the bottom of the armhole if you're not adding the sleeve.

How much? I find an inch or so tends to be about right, if the pattern is fitted, and assuming the armhole started out at a good set-in-sleeve depth for the wearer in the first place. You might get away with tightening the side seam slightly too, if necessary, but IMO it's best if anything sleeveless is fairly fitted in the shoulder/underarm area to begin with (meaning the right amount of dart shaping, and not too much bust ease). Otherwise, gaping is a likely result. An 80s/90s-style boxy, drop-shoulder, low-armhole top would not be the best starting point for this.