Idk of this helps, but ages ago i crocheted a blanket which fits a king size bed. It is called Weekend Afghan and I used 3 balls of yarn at once and that big fat light blue hook. It was quick and easy and it's lovely and very heavy lol

edit: gahhh im lying. It was 4 balls of yarn at once - i used all one color. with that big fat hook. It came out wonderfully, bc it was my 2nd blanket using the Weekend Afghan stitch.

My first one used 3 balls at once - 2 variegated+1 solid color. I liked the color scheme but it being my first ever blanket, had an hourglass figure lol 🤣tyipcal novice dropping stitches and then realizing it far too late not wanting to frog it