My evidence requirements are actually pretty simple. I feel that we need a two part test. At some point, both Jesus and his father would have to be physically present.
1. Does the alleged Jesus have supernatural abilities that indicate he could possibly be the son of god?
2. If the answer to #1 is yes, then the next step would be getting god to claim him as divine progeny.
For #1, I would simply ask Jesus to duplicate his most famous trick - death and resurrection. He could agree to be put to death via lethal injection or if violence is required for the trick to work correctly, a firing squad or even a full on crucifixion could be arranged. Once a team of medical professionals confirms the death of "Jesus", his body would be placed under 24/7 watch using a combination of human and technological resources. If after a week, the body is still dead and the "Jesus" has not reanimated then game over.
If the #1 test is completed, then "Jesus" would have to summon his father to earth to vouch for him. My requirements for this test are very simple and shouldn't take god more than a few minutes to complete. I want god to physically appear, make a definitive statement that the alleged "Jesus" is really his son and then they depart in some kind of deity appropriate fashion. Something like bareback on the tail of a comet would work just fine.