sorry-- the threaded inserts go into the neck, not the body.
Here's a FAQ from someone on the TDPRI page--
I've used threaded inserts for years on all my guitars. I've tried them all and the very best are the steel knife thread models made by E-Z Lok
http://www.ezlok.com/index2.htm
I use the model 400-3-CR. 3/8" OD with 10-24 threads.
These steel inserts are much easier to use than the brass. The brass have very coarse thread and are exceedling difficult to put into rock maple.
You'll note that they have a special hex drive insert tool for these inserts. This is essential, you can't put them in with a simple screwdriver. But, using the tool and a wrench, and going slowly, it's easy enough.
A couple of caveats: do some test runs in hard maple before working on your neck. Make sure you are completely comfortable with the process before working on the neck. Also make sure you use some kind of lubricant on the outside threads of the insert. Soap, wax , or a telflon spray will work fine. Go slowly too.
Once you've got them in your neck you'll see a couple distinct advantages over the traditional woodscrews. One, you can remove and replace the neck countless times with absolutely no hassle. Two you'll be able to tighten your neck to the body with considerable force which should help a little with sustain.
Hope this info is useful.