[Closed] Anyone want to talk to me about P-traps?

I'm currently "discussing" with the kitchen fitter about a high loop for the dishwasher before it plugs in between the sink and the P-trap. He's put a tee piece in which also creates a backwards fall.

How high does the dishwasher drain loop need to be?

Does the size of the P-trap matter? Instead of waste in the U piece, it will now fill the whole P-trap and the "fall" pipe all the way to the external wall.

Any advice?

Does the hih loop need to go as high as possible or just higher than where the system drains to the outside?

It's a 1.5 bowl sink with a low barrier between rather than a typical sink overflow if that helps.