@xoxoashlee you can calculate the length based on how long a certain amount of rows is in a bracelet you made previously. It depends on the material you use and how tight you knot.
@imabilly_ since you have made alphas before, you can take an alpha you have already made and measure how long a certain amount of rows is. From this you can calculate how long 141 would be. I think 90 inches would be too long.