Specs cost money — minimize the bill
Anyone can hit a purity spec by throwing energy at it. The job is to hit it economically. For a distillation column the dominant operating cost is the reboiler duty, so a good design meets the purity at the lowest reboiler duty that still works.
You'll use the Case Study tools in Analysis to sweep reflux ratio against reboiler duty and find the sweet spot, then lock it in.
Meet the spec at minimum reboiler duty — that's the design, not just any feasible column.