Yeah just jump in and have a go. The only thing from my Skitarii that I magnatize is the Onager for different gun options. Have a look at my Sidera Maris plog. I did a mini tutorial for doing that. Now to stop being such a magpie about these things and get into my Skitarii box and get them taken care of.I'm in a similar boat, but with Skitarii instead of Tau and have yet to actually try the magnets. Yours look good, though, I'm excited to see the models painted!
OT Liking what I'm seeing, the fix on the ethereal looks good. Maybe, sand/scrap the line of GS smooth a bit more before priming. Wasn't there a suit or three with that box?