my call for response is not, "Decide today to follow Christ!"
I was puzzled why you would reject this. So I posted an appeal from famous Calvinist Charles Spurgeon with similar language:
If God be God, serve him. Decide quick
To which you responded thumbs up, saying it would be the elect who would respond.
So why are you so opposed to you yourself using that appeal? Do you have some extra beliefs beyond what Spurgeon held that are motivating your quibble?