You'll learn a lot from watching your Trainer body clip - I had to teach myself when one of my geldings was diagnosed with Cushing's Disease a couple of years ago. I made some 'mistakes' the first time and met with some difficult areas to properly trim but I just took my time and it all worked out. Now I do a pretty respectible job, even if I do say so myself!
I had been borrowing Oster Clipmaster clippers from a friend - they do a SUPER job but were a bit high priced for my budget. I ended up getting Andis AGC 2 - they are much easier to handle - actually the size of normal clippers. They came with a T-84 Ultra Edge blade and it made easy work out of body clipping! For me, they were easier to navigate in those hard to reach places, too. Plus, they came with an instructional body clipping VIDEO which teaches all the tricks of the trade! It even went into how to properly use and clean the clippers. I REALLY like the Andis AGC 2 - I wasn't sure they would stand up to body clipping but I was pleasantly surprised! Good luck on your search - there is SO much out there to choose from! The Andis AGC 2's suit my needs perfectly but I only have to body clip my guy about twice a year - your choice will have to fit your needs. The Oster Clipmaster clippers did an awesome job - my friend has used them for years. If they had not been too expensive for me at the time, I would most likely have bought myself the Clipmasters. However, I am not at all disappointed with my Andis AGC 2's and can highly recommend them!