After a so-so summer of racing in very light and changing winds at regattas, I had the opportunity to ask two FD experts the same question about light air sailing. I got two quite different answers both very interesting:

Question:
As the wind rises from nothing to, say 10 knots what changes do you make to the rig, which controls are the most important?

Dave Fagen III :
When the wind changes you should think from the beginning.  Almost as if you just put the boat in the water you need to re-tune the rig, and the most important aspect is the leech of the jib:  If it is too tight you will have no speed and too loose no pointing ability. I tell people to pull on the jib halyard until the telltales on the leech start to stall and then let it off until they flow. Everything else can fall into place from there, assuming that you are trimming the mainsail in to at least centerline and not letting the leech of the main twist off too much.
In 3 kts I sail with the mast pretty far back to keep the slot open, and as the breeze builds I pull the halyard up and the movement of the mast forward tightens the shrouds and the leech to help the boat point into the wind.

Enno Kramer :
At Beaufort 1 you have the lower stays loose, the shrouds plenty loose, and also the genoa sheet not all the way down. As the wind increases to the point so the crew is thinking of going on the trapeze gradually pull in the lowers so the mast comes up straight. At this point the genoa sheet may be brought all the way in, though with the blocks still above the deck. Also you'll have some tension in the shrouds by now. Once the crew is fully in the trapeze you can pull the genoa blocks down to deck level.
Furthermore, while the crew is still in the boat the highest telltale (on the main) should only now and then stand out straight. Once the crew is in the trapeze this should be flying steadily aft. You can see to this with a combination of main sheet and vang tension.