I like April 15 too.  I don't know if you mentioned any of these points yet: (if so, sorry for repeating them)
*April 15 is a Wednesday.  However, in Matthew 25:6 it states that at midnight a shout rang out.  In ancient Jewish weddings, the bridegroom would come on a Tuesday night.(Thanks JR Church).  The Bible says the groom was long delayed.  So on April 14 it will be a Tuesday, in following tradition.  One second after Midnight it will be April 15.  How perfect!  The shout at Midnight Tuesday April 14Th.  Seconds later, the rapture. (April 15Th) I believe it most likely will be Israel time.  So for me, it would be 4 in the afternoon.
*Also in Matthew 24:32 it states "When the fig tree sprouts leaves.....the lord is hand"  I have found photos of fig trees in March (in Israel) and they are just sprouting.  At hand means "the near future".  April 15 would be the near future of March.
*The last day of unleavened bread.  Moses was instructed to celebrate the festival of unleavened bread to honor the removal of the Jews from Egypt where they were being enslaved.  Sounds like God coming to the rescue.
*Finally, I looked at Israel climate on line.  The rain season stops in April.  Song 2:10 says, "My beloved spake, and said unto me, Rise up, my love, my fair one, and come away.For, lo, the winter is past, the rain is over and gone....


Take care,
Bjr