First, does it not seem reasonable that God, the Great Evangelist who is doing 95% of the overall work and who has already been relentlessly shouting at everyone every day, would probably send His servants to proclaim the gospel to those whose hearts are the most receptive rather than those who are least receptive? I would think so.
Does it not also seem possible that God, the Great Evangelist who has already been preaching to all people every moment of their lives, might chose not even to bother sending the gospel to those who are completely ignoring everything else He has been saying to them for years? Why should He waste His efforts telling people the last 5% of what He would like them to know if they have been completely ignoring the first 95% of what he is trying to say to them? I would think that it is more likely that God would send judgment upon such people hoping that they would soften their hearts. If and when they did, then it would seem logical to think that He would send His servants to proclaim the gospel.
Some might say that God will send His servants to those He knows will not repent so that they will be without excuse when they stand in judgment before Him. Keep in mind, however, that according to Scripture, such people are already without excuse before God because of His never-ceasing revelation of Himself through His creation (see Rom. 1:20). Thus if God does send one of His servants to such people, it is not so they will become accountable, but so that they will become all the more accountable.
If it is in fact true that God would more likely lead His servants to receptive people, then we, His servants, should prayerfully ask for His wisdom so we might be led to those He knows are ripe for harvest.