I bought the Lift-a-Dots from Soft Bits for Sevens:
http://www.softbitsforsevens.co.uk/
I used the double height, M5 thread ones (part number 340). I chose double height to get up over the tub front lip, as that was what was on the ute. You could also do single height ones (also in M5 thread). They are cheap enough to buy both and see what suits.
From memory I bought the nutsert gun from eBay, though Bunnings sells them too. I bought some M5 stainless nutserts off eBay. It's probably overkill, but I did not want galvanised nutserts to rust out. When you form them, they damage the gal coating... pretty fair chance that they will corrode. Go gentle on the nutsert gun... if you squeeze the crap out of it, you will tear out the nutsert. Happy to loan you the nutsert gun if you are in Sydney, though freight would make it just as cheap to buy one if you are not local.
I put a small stainless washer under the Lift-a-Dot before I screwed them into the nutsert. The Lift-a-Dot hex heads are bigger than the nutsert, and if you turn them tight there is a good chance the hex head points will tear the paint.
Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.