Having more beads than you need is not a problem, they regulate humidity both ways, they will release it when dry and absorb it when it is too wet. :tu
I still like to have a hygrometer if for no other reason than peace of mind. You invest all this money in the hobby, why not $10-15 more in a digital hygrometer. :2
Good point, I'm placing an order for the beads and hygrometer tomorrow morning. :tu