www.makemkv.com

I am looking for the optimum set of parameters for use in Handbrake AFTER extracting video from blu-ray discs containing 73 episodes using MakeMKV.

I will be looking for MakeMKV's default compression parameters later, to add to the analysis.

The question that interests me is, which has better visual quality, a 1080p scaled down to 720p, or a 1080p compressed down to the same filesize?

Thank you

I will be looking for MakeMKV's default compression parameters later, to add to the analysis.

MakeMKV does no compression; what you get in the MKV is the video that was on the disk. So, as far as a comparison, you should consider it the starting point.