well thats one of my favorite tricks,, I think I may have said it once or twice,, not that it matters it isnt my idea, I stole it,,
as for an advantage, there are two dramatic advantages to sheeting OVER the trailing edge strip. the first is that you dont have a glue seam to try to hide when you are finishing.
the other more important advantage is, the trailing edge is Locked into place by the sheeting and is in my opinion a much stronger setup. This is the way Pat taught me to do it and every plane of mine has it that way. to sand it down to the correct angle is in fact quite simple. I use two inch tape,, automotive 3M painting tape from a body shop supply. Yes it IS expensive,, but not any more expensive than that pretty balsa wood you are protecting. its a tool, and good tools make good models, plane and simple,,,
I lay a strip of 2 inch tape acros the ribs after the trailing edge strip is in place, then you can sand aggresivly with a long sanding block until you are down to the tape. peal the tape, and sand with fine paper to remove the last bit of the trailing edge down to the ribs. If you tend to be a bit heavy handed or unsure, place another strip of tape an inch or so up from the trailing edge across the ribs, (leaving the exposed section narrower than the sanding block is) then you can concentrate on working the last bit down without sanding grooves in the ribs on the other edge of the block.