Rumo Price: $7.00 Print On-Demandcardigan knit in modular pieces, with open front and set-in sleeves to fit bust 30 - 53" with 3-5" ease uses 1095 - 1985 yds worsted weight yarn
I modified this to make a vest (size 50") using Noro Akari and just went into the 3rd ball, so you can probably get the 50" sweater out of 3 balls.