I have adjusted the armscye on my muslin for a coat, making it slightly larger along the lower half (front, back, and underarm seam) per advice from a tailor friend of mine. But now the 2-piece sleeve’s cap is about 1 1/4 inches too small. I’ve found lots of info for making a sleeve cap smaller, but not on lengthening it. Should I reverse the “making it smaller” instructions by slashing and spreading, or is there something else I need to know? Thanks for any advice.