Feature Request: Customizable window size

[bigfinfrank]

This would be a PR but the source code isn't available yet so (at least for now) it's a request.
Is there any possibility of setting custom dimensions for the window? Scaling the window source in OBS will never look as good or be as accurate as changing the source resolution. 300x300 is a bit on the smaller side, especially for people who stream or record and post VODs/clips at higher resolutions (1080p, 1440p, 4K, etc).

Reference image of 300x300 squares at different resolutions

This may not be exactly pixel perfect but it should be within 1px and it's a good graphic for how small the visualizer can appear at it's native resolution.