We are installing a bathtub in an alcove with three walls (which we are tiling), and we are planning to put a short tile wall on the exposed side of the bathtub. As a result, we are planning to get a ‘drop-in’ style tub. Do we need to get a tub that has an integral flange on three sides? If so, I am having trouble finding a 5′ by 30” tub with an integral flange on three sides. Any suggestions? Thank you.