For 5 hens, you only need 2-3 nesting boxes. Two is plenty. You can consider a shared larger box arrangement, but it depends on your pecking order.
When they have a favourite box, they have a favourite. I had two boxes for three hens, and if a 'peak hour' rush came on, all three would try to cram into one box.
They will always lay in their preferred spot. And if the nesting box/es are not 'up to scratch', expect 'complaints'. I am integrating new pullets at the moment, so some temporary boxes in the mix. One of the pullets is still not happy with what she was used to (low box, compared to really high box from the breeder). She is the 'ginger whinger' (buff orphington). Ah, she'll just have to get used to what she is offered.