Passover

My feeling about Passover is that it ought to be based on the molad [conjuntion], not on the day after the molad when the moon can become visible. My reasoning has nothing to do with the Gemara in Rosh Hashana where it is clear that the time for setting the time of the new moon is after 18 or more hours after the molad. Rather my reasoning is based on the Gemara in Sanhedrin where R Elazar said that if the lower court does not sanctify the new moon in it proper time, then the heavenly court does so. I have thought for a long time that the called Hebrew Calander is simply copy and paste of the Calander of Athens. I also think that while it is good to do spring cleaning, however to base that on chametz is disingenuous. After all, to get rid of chametz all one needs to do is to say all chametz that is in my possession is null. And that is enough [as long as one’s intention is sincere not to eat or posses chametz during Passover. However, the bill of sale that is customary I think is invalid based on the Gemara in Ketuboth where a mother signed all her possession over to her daughter without it really being sincere, and when he recovered her health the property wag oven back to the mother. A bill of sale has to be with intention to do the sale, not a trick to avoid the law.