I'm using a Shimano 2x Di2 setup on my gravel bike and I would like just a little grannier granny gear. I'm curious . . . is anyone using an 11-36T cassette with a Shimano Ultegra GS rear derailleur? I've heard of sightings -- kind of like bigfoot -- but I've never talked to anyone who has used it. If you have tried it, how did it go? Reliable? How's the shifting? Any problems?