I am putting a drop in tub in an old house, floor is not level
If I build the frame for the drop in level, knowing the tub won't rest on it, can I just level ithe tub with the morter on the bottom when I drop it in?
Yes. Structolite (sp?) or deck mud would both work. Slap some piles down there, then smush the tub down into it until it is level at the height you want.