Toilets, Sinks, Showers, Tubs and Disposals - Tub Support Question (Mortar)

Thanks to your pro posts I'm convinced that putting a layer of mortar under my new tub is not only recommended but neccessary! thanks!
However, I'm ending up with 1 1/2 space b/t the bottom of the tub and the floor and it seems like an awful lot of mortar to be putting down. I'm all for slapping down as much as needed but will it end up oozing all over from under the tub?
Should I be building some sort of a frame to fill with mortar and then to set the tub into?

Also, the installation shows a 1"x2"x56" piece laying on the floor at the base of the apron. It's not clear from the directions or the picture where it is exactly, but I'm assuming it's on the inside of the tub. Is it for side-to-side support?

Thanks for your help,
Mika

Yes. The mortar will ooze out and "cup" the bottom of the tub. Mix it up sort of tight and whereever you can, use your hands and dam it up against the sides of the tub.

Not only will with give support but it will control sound issues and insulate the tub in regards to maintaining warm water.

Yes. The mortar will ooze out and "cup" the bottom of the tub.

How do you mean, by it will cup the bottom of the tub? In what way?

Meaning the excess, depending on how tight you mix up the mortar, will ooze out and roll up on the sides. This in turn conforms to the edge of the tub and "cups" the unit.

I then let it set up for an hour and come around and hand pack the mortar tight to the tub so that it provides the best application.

Ahhhhh. O.k.. So then it is not hurting the tub by somehow causing the bottom of the tub to cup. I follow.