Allow flexible size for containers like App Switcher

I really like the App Switcher. Before I started trying out BTT, I was specifically using TouchSwitcher which gives you a button on the right to make it appear and when you use it, the container uses enough space to display all icons.

I'm not asking for an exact copy of their UX, but what I am trying to do right now is find a good size for the switcher to appear on the right which will not leave an empty gap if I only have a couple of apps open, but doesn't require a lot of scrolling if there are a lot.

Being able to set a max size instead of a fixed size, and letting the container size be flexible would be a great improvement for me.

I would also like to see a way to make widgets a fixed size. For example the Now Playing widget changes its size depending on the length of the song/album title. Would be nice if we could reserve a space for the widget on the bar that is fixed in size and the text is always centered within this fixed space!