just as a rough guide.... in parachute dropping you will know your ias for the whole climb and jump run.... work out before the flight the tas you'll expect for every couple of thousand of feet up to drop altitude. if atc/traffic allows it, do a circling climb on the first run of the day and compare gs v tas ie gs will increase when turning onto downwind and decrease when turning up wind.... this will give you a good idea of wind on climb. also if cloud is present have a look at the direction its travelling... since the jumpers will be under canopy at about the same height, this is quite useful. get yourself established onto the jump run early for the first jump! use gs v tas and drift to get an idea of winds aloft (we would use the forcast wind as a starting point for the run direction) then adjust it as you fly the jump run, either by offseting the run into wind or even a different track. late in the jump run is not a good time to be pulling out the wizz wheel... just take a rough guess!!
after the first dump.. have a chat to the jumpers and refine the run direction... it the winds are completely different than expected late on the jump run, dont hessitate in telling the jumpers to stay in the plane... and reverse the run direction.... it better than picking them out of trees and off power lines!! im sure you'll find plenty of opinions from jumpers on how to fine tune the run!! hope this helps!