It's an American Standard Rope Twist tub, 60 x 32, acrylic. The directions just tell you to make a mortar bed, nothing specific. I can raise the drain side about 7 inches before the end piece stops itself on the wall (but this is only in one spot--when it is almost in place). Why don't they make a pumping mortar-thing like they have for foam insulation like they do around windows? Too thick? Anyhow, what about this plan: maybe I can dump a pile of mortar on a piece of plastic that runs up the back wall too. Then after sliding the tub in, I can raise it up on the drain end and pull the plastic sheet back into place (if it moved) and add a little more on top and then lower the tub? Never using mortar before, I have no idea. What do you think?