** UPDATE **
In another post I had asked about using the mobile menu across all devices. I did that now and this also accomplished centering the logo

For reference, if someone else is looking to do this: 
1. Navigate to /public_html/media/astroid/assets/vendor/bootstrap/scss/
2. Edit variables.scss - find the breakpoint section and adjust (here is what I used)
// Grid breakpoints
//
// Define the minimum dimensions at which your layout will change,
// adapting to different screen sizes, for use in media queries.

// scss-docs-start grid-breakpoints
$grid-breakpoints: (
  xs: 0,
  sm: 576px,
  md: 768px,
  lg: 992px,
  xl: 1400px,
  xxl: 2500px
) !default;
// scss-docs-end grid-breakpoints

@include _assert-ascending($grid-breakpoints, "$grid-breakpoints");
@include _assert-starts-at-zero($grid-breakpoints, "$grid-breakpoints");


// Grid containers
//
// Define the maximum width of `.container` for different screen sizes.

// scss-docs-start container-max-widths
$container-max-widths: (
  sm: 540px,
  md: 720px,
  lg: 960px,
  xl: 1340px,
  xxl: 2420px
) !default;
// scss-docs-end container-max-widths

I still would love the menu to show on the right and slide from right to left. I think. Maybe I'm happy the way it is LOL
And, I guess my question is: Will this file be overwritten by future updates? If so, how can I preserve these settings?

Thanks so much!
Gina G.