if running a quick connect, wouldn't it be advisable to step up one or two sizes at the disconnect due to the reduced id. of the disconnect fitting ?
Yes.

This is the best moment to plumb a good hydraulic cartridge filter in the line from the trans to the cooler.
Before the trans actually fails, the worn-off clutch and band friction material comes loose and circulates, which screws up your pick-up screen, pump, valve body, and converter.

Copper will work harden if you let it move. When it doesn't, it lasts for 20 years, like in your refrigerator.