How to convert short cage rear derailleur to medium cage (Shimano Ultegra 6770 with 6800 cage)

I took a chance and bought Shimano Ultegra 6800 inner and outer plates (derailleur cage) to convert my Shimano Ultegra 6770 di2 rear derailleur from a short cage to a medium cage. I'm using a 34-50 front crankset and an 11-34 rear cassette with this combination. I also use a Sunrace derailleur hanger extension. I didn't need to adjust the gears from 11-28. I did have to adjust the derailleur hanger extension.

Correction: The Ultegra 6800 is listed to have a 37Tooth capacity. The ultegra 8000-gs has a 39T capacity.

Table of contents:
0:00 Introduction
0:27 Parts / tools needed
0:53 look at SS/GS cages
1:24 tooth capacity explained
2:27 remove short cage plates
6:28 look at outer plate and spring assembly
8:17 weight comparison of cages
8:44 ss/gs cage visual differences
9:53 GS cage INSTALL
14:25 look at ceramic jockey wheel
17:08 reason for upgrade
17:42 testing new setup
20:04 another view of conversion
20:18 Conclusion