Well, shrinking it all together would be quite some work I'm afraid. Deleting or "disabling" certian meters is easier: Just hit right mouse button and "edit skin".
From there you can comment out (#) the meters not needed, or delete the lines.
Search for "#for HDD usage in left panel"...
Just thought I'd share a rainmeter skin that I've adapted to using HWiNFO sensors.
The original artwork is from by shanqs12 from http://shanqs12.deviantart.com/#/d5iqydv - I only edited the skin and added a few things here and there.
You should in theory only need to edit the...