Okay, I see. Sounds like a risky operation. I think I'll stick to component era consistency and avoid combining 2009-2014 parts with 2015- parts.

Speaking of the 11-speed Chorus group I just got, it shifted like a dream on the workstand, but on the trainer the upshifting on the middle cogs is actually delayed a bit, which is something I've never encountered before. Normally a fresh derailleur install results in having to tighten the gear cable to get the downshifting going properly, so I always make sure to have the cable stops and barrel adjuster screwed all the way down to allow for ample cable tightening, but now it looks like I might have to dismount the cable on the rear derailleur and back the barrel adjuster off so there's room to loosen the cable.

Wild.