Rear brake flex hose question

Motive Products 0105 Pressure Brake Bleeder, Square Master Cylinders | eBay
Motive 1103 Chrysler Brake Bleeder Adapter | eBay
I don't know if you familiar with the Motive pressure bleeder but I've had one for many years. They are a life saver, plus you will be amazed how little fluid you will use even for a brand new complete system. The second link is for the later model Mopar MC.
Yes I've seen those , never used one. I have a Harbor Freight that I like also uses very little fluid. I bleed the old fashioned way back to front and even gravity flow.