Decision Time

I've done the seven repeats of chart 1. Do I chance it and do another repeat? Or do I start chart 2? I want to use up as much yarn as possible. I am also in the solid purple of the yarn. I believe this means I should have half a ball left. But it doesn't look like I have that much left. Tomorrow I will weigh the remaining yarn and see.

I wonder if there is some way to calculate if I have enough yarn left to do another repeat or not.