Specify minimum horizontal spacing

[stevage]

First - this is a really great library, thank you very much.

I don't seem to be able to find a way to influence any of the spacing when drawing a bar. I'd really like to be able to specify a minimum horizontal spacing for each beat, in order to get different bars (which are rendered completely separately) to line up with each other.

My use case is perhaps a bit unusual, I'm writing a composition tool that involves lots of separate scores:

In this example, each of the score fragments in a vertical column should be vertically aligned on each beat.

Simply passing width: 250 when creating a new System does not seem to work: the bars are all the same width, but the beats don't line up:

Any suggestions for how I could go about this? Happy to modify the library with a bit of guidance, and perhaps submit a PR if welcomed.