Rhino should have a section command, I am quite surprised it hasnt.
1) select start of section line
2) text at start
3) select end of section line
4) text at end
to use same options as leader
having to try and construct a two arrowed line is a bit primitive in such a progressive program.
I used two leader arrows and didnt type anything then moved them about using control points,it took a bit of time.
Glad I only had one to do !
This must be one for the V6 wishlist unless anyone cares to do a code.