New Kitchen Backsplash. Sheetrock Prep...

We are having new granite counters installed. The counter installer required us to have the old backsplash removed prior to templating the new one. The contractor removed the old backsplash and sheetrock. He patched back in with new sheetrock/mud.

The old counters are still there and next week the counters will be removed. The problem is that the new sheetrock is not flush with the old sheetrock that is currently behind the counter.

The new counters are a 1/4" thinner and therefore there is a gap some places as big as .25" where the sheetrock taper met the old sheetrock.

What shall I tell the contractor if he tries to lay backsplash over a wall where there is a gap between the new and old sheetrock as well as part of the sheetrock sticking out further than the other?

Will the adhesive make this up or should i require them to mud/sand this gap prior to installing new back splash?

 

Which drywall sticks out further - the new or old? by how much? Does the repair go from one corner to another or does it open up into a wall?

 

View image: IMG 0060

Here is a pic taken behind the sink.

 

Figure your contractor knows what he is doing.