Since it has again been awhile, perhaps someone new looking in who thinks the crucifixion took place on the 6th day of the week and who thinks Matthew 12:40 is using common Jewish idiomatic language where 3 nights actually means 2 nights, and who thinks that the "heart of the earth" is referring to the tomb, will know of some writing.
You have yet to find anything wrong with the following :
IMO, I see Mt.12:40 fulfilled in the following way:
The Hebrew day begins at sunset the day before and fulfills the prophecy:
Wednesday @ sunset = Thursday = 24 hours
Thursday @ sunset = Friday = 24 hours = Passover Sabbath
Friday @ sunset = Saturday =24 hours = seventh day Sabbath
Sunday morning, first day of the week = Jesus resurrected.
Describes Jesus in the tomb for three days and three nights, confirming Mt.12:40.
Quasar