Sand or Stone Dust

Good day to all,

I'm new to this forum. I will start installing a 15 x 24 pool this weekenk. I've read the instructions carefully but I'm still unclear on a few points. Maybe some of you could help me. This is a buttress style pool but instead of strap, I will pour concrete sidewalk on each side as per instruction. I will be installing a bottom drain and sloping the pool 6" deeper in the center .

1)I've started removing the sawd and level the area. The instructions mentioned that I will need 2 1/4 ton of sand and 1 1/4 ton of stone dust - or 3 1/2 ton of sand only. Which is best? All sand or stone dust under with sand on top?

2)What is the proper procedure once everything is smooth. Do I tamp down the dirt with a vibrating plate before putting sand/stone dust layer? How thick should the layer of sand/stone dust be?

3)Will I be able to tamp down the sand even if my pool bottom will be slightly sloped?

Tx for your help

Yves