Normally, this would not be a problem.
I’m in the process of making a sweater for my son. I substituted KP Sierra (now Cadence), 100 gram skein 110 yards for Crystal Palace Cameo, 50 gram skein 77 yards. The pattern called for 17 skeins of Cameo (1309 yards total). I ordered 13 skeins of Sierra/Cadence (1430 yards). I have completed the front and back. I added 3 inches in the length from the cast on to the underarm bind off and 2 inches from the underarm bind off to the shoulder. I still have to knit the two sleeves (with a pattern block down each) which I will lengthen approx 2 inches.
Cameo is a tubular chunky weight while Sierra/Cadence is your normal chunky weight spun wool. My gauge is spot on.
I still have 6-1/2 skeins/balls of yarn for 2 sleeves and the neck trim. Doesn’t that seem like a lot of extra yarn? I probably could have ordered one less skein, but that is still 5 skeins left.
It looks OK. I haven’t fit it on him yet, but I’m getting awfully nervous.