SQ-hosted video non-standard aspect ratio

Site URL: https://www.vandersteurdesign.com/flash-plus-music

Trying to lose Vimeo as a video host by using Squarespace video blocks for a few short vids. (Great new feature, btw.) I have non-standard aspect ratios but want the videos to fill the width of the blocks without cropping. Have not found the right code yet, if it exists. So far, the SQ videos float within the block, revealing the gradient extending out to the edge of the block. If I extend the video using black bars to a 3x2 ratio (or whatever), it will probably fill the block but the vid will still be smaller than I'd like. Could use more info on these new video blocks. In the meantime, can anybody help me :

• Fill the squarespace-hosted video block --side to side--with a non-standard aspect ratio?

• Attaching a screenshot of a Vimeo embed and a SQ video block below it.

Thanks. -gary