In FT windicators certainly help, one eye on the Windicator and then observe what is happening down at and between the target. It helps spot those sneaky wind changes you get, I don't smoke but always watch the smokers to see whats going on.
There are a few with talk puffers I've just got one to try, def helps when it appears calm as it shows the slightest of drift.
so I'd say smoking and watching the effects will give you a guide. It has to to used as part of the puzzle though not alone as there's a long way between the cig and the target (well in FT anyways ;-) only kidding).
Windicators, talk and cigs legal in FT
Steyr LG110 FT, Sightron SIIISS 10-50x60 LRIRMH