Compression default of v5?

[mck]

I hope next version allows us to change in the backup settings

We will implement this feature as soon as possible, but there is no guarantee that it will be available in the next release.

If an image backup at low compression results in a 100 GB file, what would the approximate file size be at medium and high compressions? 

Trying to determine if going to medium or high compression is worth the time or risk.

Thanks for any insight on this.