Considering light a wave or a particle will make no difference in this instance.
The location of Jupiter wasn’t planned.
The correction for Jupiter’s gravitation is a calculation which has been proven to be correct empirically, independent of theory.
The determining factor here is the shape of the bent light lens pattern.
If gravity is instantaneous then the pattern should be round because the gravitational field is spherical.
If the shape is elliptical then the gravitational field is an ellipsoid with each layer of the field reflecting the position of the mass when it was emitted indicating a time delay for gravity travel.

This does not prove that gravity travels at the speed of light.

This does prove that gravity is not instantaneous.
It would take a an error a lot greater then 20% to allow for infinite gravitational velocity.

The only thing we can question is the data, and the calculations.
Unfortunately it has been several months and if there was a flaw in the calculations it would have been pointed it out by now.
There are a lot of people involved in this that would love to show they are smarter then everyone else by pointing out a flaw in the calculations.
As far as the data, a lot of people were involved in this to coordinate the data gathering points from all over the world.
This isn’t some guy working out of his garage or even a group from one university who might be inclined to cover up a mistake.

I think we may have a better chance picking winning lottery numbers then winning the infinite gravity velocity game.