So, in othe words, Christian apologists can speak as irrationally as their wish, and as long as we have the Holy Spirit they are off the hook. Curious position, but it explains a lot, esp. why dispensationalism is so popular. It matches the irrational times we live in
They will be judged in accordance with the knowledge and wisdom with which they have been entrusted.
Beyond that, as a Calvinist in the Tradition of Arminius, I would have to say... no harm, no foul.
Skeptics will not be excused at the judgment for failing to respond to the call of the Holy Spirit because some dispensationalist confused them. Nor is there anything any one of us can do to somehow use our own powers of persuasion to convince some skeptic of the truth of scripture.
God will have mercy upon whom he will have mercy and if he chooses to show mercy to some skeptic, then he will obviously convince that skeptic of the truth of scripture as part of the process.
FWIW there is nothing logical or reasonable about the gospel message. Skeptics do not need to point to the words of irrational dispensationalists to find a reason NOT to believe. They can point to the arguments of preterists and reconstructionists and replacementarianists as well. To the natural man all of this stuff is foolishness. You will be barking at the moon if you think that your version of eschatology is any more rational to a skeptic than that of the dispensationalists. They think we are all nuts and if you think you can convince them that you are not as nutty as a dispensationalist and therefore they should follow Christ because your gospel is more reasonable, then you are nuts.
We cannot convince the skeptic of the truth of the gospel. Only God can do that. And if God has determined to convince some skeptic of the fact, then there is nothing Tim Lahaye or Gary DeMar or topcat or Marlowe can possibly say that will dissuade them from that decision.