I currently own a Sony PD170. Has anyone been able to successfully use the magnet trick to flip the image with this camera? If so, how is it done?

if it has self shooting mode then You can try to find it from right edge of EFV. Best magnet i've found is HDD head servo magnet. You can just break just little coin size piece from it and try.
But anyway it's not good option. Just because You have to see image from relatively large VF to have it in focus correctly. 7 inch is minimum imo.
All work i've done with camcorder FV is slightly incorrectly focused or happen to be in focus... You're never sure. 7 inch extra FV virtually eliminate this problem.