It's not really so hard on the mac. OK it's 3 steps. But once you've got the technique it's the same. It might take a little time that's all.
With DVDBackup I extract to a folder. OR With Yade X I extract as a dmg. Then I mount that dmg using Disk Copy by double-clicking the dmg or drag & drop. Then I open DVD2oneX & direct it to the mounted image & shrink it from there. I set up a custom size within DVD2oneX because some dvd's shrink differently to others (stick to the preset size .. it's generally very reliable.) I also use Verbatim DVD-RW's which can fit an extra 10 mb or so on (ie: 4.37 GB.)
Only semi-related is Compressing file to fit on one 4.7GB DVD-R But that's burning vids to dvd not to do with extraction.