Like Chuck says, it's not difficult to get used to - it only takes a modicum of practice. Hundreds of instructor trainees do it every week all over the world.
If you instruct a lot it can even get to the stage where you're more comfortable in the RH seat than the left for a particular a/c.
FFF, I never had a problem with it in my past CFI positions. As long as the pilot demonstrated competence then they could fly from the RH seat to their hearts content.