What are the parameters of the grid under Bootstrap 3 for phones (resolution 320)?

Question

Design

I already have ready-made layouts with grids with container width: 1170, 970, 750 (all + 2 indents of 15px) with 12 columns, 30px width of the middle. The bootstrap site lists the ill-fated "auto" in the mesh data.
Can you please tell me what width of the container to use? How many columns? What is the width of the middle? If you make the width of the container 290 px (+ 2 indents of 15 px each) and the middle 30 px, then unfortunately there is not enough space for 12 columns...

Answer 1

At 320, 6 columns are used.
I throw a link to the PSD template, Boostrap 3 grids, it will answer all questions: https://yadi.sk/d/jI23eWQYfCfMN