Final Cut Pro Picture in Picture template
if you have Apple Motion you could make a template which would be easy enough and just drop it on when you need it in the video and then drop the additional image onto the motion template.

OR

(I am going to assume you know how to place 2 layers of video (top one being the PiP one))
the first time you want your PiP get it placed where you want it with all the sizing, placement etc. Then when you want to do it again in the next section just copy and paste the attributes from the first one onto the second one and it should place it in exactly the same place.