Help with decreases

Hello!

I am knitting my first colorwork sweater right now, and had to knit a size up for the yolk in order to meet the gauge with my tighter knitting. However, I’ve been working on the body now and I’m realizing this size is WAY too big on me in the body, like 10 inches of positive ease big. I want to keep the size for the yolk, because it fits well, but size down one size for the body for a better fit.

I did the math, the smaller size (2) will end up with 234 sts for the body and the larger size (3) will end up with 254 sts. I need to dec 20 sts in total.

There are a couple ways I can do this, cast on less underneath the arms (though I’m not sure how this will affect the fit of the garment, so I don’t want to do TOO many less. Right now there will be 16 sts under each arm for size 3), I can also decrease the 20 sts throughout the rounds. I’m trying to figure out how to do this quickly, but also neatly without affecting the look too much. I was thinking of decreasing under the arms and/or in the center back.

This is super long winded so my apologies but would greatly appreciate any help/insight people have!