John 19 - Jesus' death - clearing up contradictions

Pilate flogs Jesus, hoping this will satisfy the Jewish leaders, but they turn up the pressure in two ways.  First they point out that Jesus called Himself the Son of God, a title reserved for the Roman Emperor.  Second, they accuse Pilate of being against Caesar if he releases Jesus.  It was Friday at the 6th hour that Pilate condemned Jesus.  He is crucified near the city with a sign in 3 languages that He is the King of the Jews.

Soldiers gamble for His clothes, according to prophecy (Psalm 22:18).
Jesus tells John to care for Mary, giving the disciples primacy over His biological family.
They way the soldiers confirm His death also fulfills Passover and prophecy (Exodus 12:46; Zechariah 12:10).
Joseph and Nicodemus, two men of means and prominence, hastily anoint and bury Jesus before the Sabbath begins.

A supposed contradiction

Mark 15:25 says Jesus was crucified at the 3rd hour, but John says in 19:14 that it was the 6th hour when Pilate condemned Him.  What gives?

The usual answer is that John was counting by Roman time, starting at midnight, making the 6th hour 6 a.m., while Mark is counting by Jewish custom, starting at sunrise, making the 3rd hour 9 a.m.  This has some credence, when we see in John 20:19 that John counts the evening of a day our way as part of the same day, instead of the Jewish way as the beginning of the next day.

Another possibility is that they are using the same calendar, but an "hour" referred to a watch, a span of time.  The 3rd hour was 3 hours after sunrise, but covers the time until noon.  They didn't refer to hour four and a half, only 3rd or 6th, depending if it was closer to mid-morning or to noon.  Since John says it's about the 6th hour, it could easily have been 10:30 or 11 a.m., and Mark was also right to say it was the 3rd hour.  This isn't as satisfactory as the first option, but it's legit.  Our modern need for precision is our problem, not the text's.