Garand Headspacing - Need Help

My local gunsmith still has had one of my Garands for a few months and I decided to spring for Midway's pull-thru reamer. It looks like a regular finish reamer, but is threaded on both ends with a larger thread on the front and a smaller thread and bushing on the rear. The threaded rod goes down the barrel and is screwed onto the front of the reamer. Now, I went to my local Books-a-Million for some gunsmithing books, but Rosie must own stock in it because the guy just turned up his nose and said in a high=pitched voice that they didn't have those things.
There is no accomodation for a tool to go one the end of the rod at the muzzle and my question is, How do I put the torque onto the rod to turn the reamer? Also, do I try to gently do it a little at a time and keep checking the headspace, or put vice grips on the rod and turn it hard?
This sounds pretty basic, but I have to ask someone.
Does anyone have a recommendation for a how-to book, and a source for such a book? I have tried eBay and have one coming, but just had to guess at the contents.
I know it's my tail if I screw it up, but I'm not getting any younger and want to lrearn how to do this and then finally shoot the two SA Garands I bought as receivers from CMP
Thanks