New Whirpool/Bathub install quagmire

[Timshel]

Hey forum,
So I built the pier for this tub, its a fiberglass American Standard 7236 model. Much to my chagrin, when I went to put the tub in, it did not rest on the pier. I cut some of the footing off and set it back in. Only now it was completely suspended by pier, half inch from floor in some spots which I planned to remedy by using mortar.
I had trouble recruiting the help to pull the tub back out and in again and I am in a bit of crunch to get this room done. A friend who does some remodeling recommended just shoving mortar underneath the tub from the rear pump access and apron side where the opening for plumbing is. Sounded like a good idea but I wasn't able to cover the base of the tub as well as I had thought. So now there is mortar packed under parts of the tub I could reach by pressing it in with tool that fit underneath

It feels pretty solid but I am thinking about cutting a piece of drywall out to access the other portion of tub and shove some more mortar in to be safe. Wanted to check here first though and make sure thats my only option. Are there any alternative bonds for support that could be used to fill the remaining voids underneath more easily?
Sorry for the long post and thanks in advance.

 

[Terry]

Normally I like to leave some space when I'm dropping a tub into a deck, and making up the space with a few piles of mortar that will squish out to conform.
You're there, so you know best if you have the support there that you need.

 

[Sponsor]

 

[Timshel]

Thanks Terry, I glued plumbing together before laying mortar so I didn't get the spread you would by squishing tub down on to a mortar bed.