A couple points to ponder Willie.....
1. God turns men to DESTRUCTION and the expected response is to repent and turn from their wicked ways...
2. The FEAR of the Lord is the beginning of KNOWLEDGE....
3. JESUS forewarned the people around him of whom they should fear....the one that can kill and cast into hell...
It is not unbiblical to use HELL/LAKE of Fire as a motivator to convince people to get right and trust into JESUS.....
Obviously the LOVE of God is also a valid tool that can also be utilized to win the LOST!
You are right, It is not unbiblical to use HELL/LAKE of Fire as a motivator to convince people to get right and trust into JESUS..... but it really works. I have never seen any actual conversions, in all my years with the Lord,when somebody preached hell fire and damnation, all I saw were false fear filled conversions and mental assent.
I have seen many come to Jesus when they met God's goodness and love and realized they were a sinner, because God's grace over powered them.
Romans 2 reminds us that it is the goodness of God that leads to repentance.
Proverbs 16.6 makes it very clear that iniquity is purged by mercy and truth first and then by the Fear of the Lord men will depart evil. A lost person cannot know the reverential fear of the Lord until they come to know him.
As you said, Preaching, teaching and demonstrating the Love of God and letting the Holy Spirit convict a person seems to be the best formula.