I proposed something conservative, not some minimum requirement. Clearly the manufacturer's recommendations are working fine for people so far.
Extremely conservative I think Brian. I'd make it simpler:
Option 1: Leave plugged in and don't worry about it.
Option 2: Drop the SoC to 50%, unplug and set a reminder to check the SoC after a month in storage. Note the drop and set another reminder to check the SoC when it reaches 30% based on your estimate of the drop per month.
After that first check, I reckon you could leave the bike for six months. That is pure speculation though. I'd love to hear some more real world examples.
For some, I bet even my option 2 might be too much hassle. I reckon that my 2014 DSP was probably left plugged in at 100% for the two years or so before I bought it. After all the head scratching I've done on this topic, I've defaulted to leaving it plugged in whenever it's at home. I don't bother unplugging it even when I know I won't use it for a week or two. That's very seldom though. It's pure laziness. I know it would be better to unplug it, but I can't be bothered to run it down before a few days off. I also don't want to forget top it up before I need it again. I forgot to plug my bike in once when I got home from work one night and it really stung the next morning!
I don't know what real world mileage a brand new 2014DS would have achieved. Mine could do about 65 miles of mixed riding when I got it, with me on it etc. I don't think that has changed after a year and 10,000 miles. Time will tell!
I wish the bearings were as good as the battery...