This subject has been beaten to death for several years now, basically since H-D went to the 18 inch rear wheels on the CVO SG and RG. And four years later there is still nothing being offered by the other tire companies that will work with the stock rims and meet the load requirements. This may be due to the fact that the number of potential customers for those particular tires isn't large enough to justify developing and producing that small volume.
If you really feel you have to switch brands, the only legit way I know of is to also switch rims to a size that accommodates tires that indeed meet the load rating requirements. As for just winging it with a lower rated tire that wasn't designed to fit a 5.00" wide rim (that's the other oddball thing about the Dunlop/Harley scam), some folks bragged not long ago about doing so and tried to convince others it was a "fine" idea that must be OK since they and a friend or two did it and haven't had a failure (yet). To me that is a really stupid way to look at things. It's kind of like sticking your hand in a live electrical box, and since you didn't get electrocuted the first few times you did it then obviously it's OK to not only continue doing it yourself but also recommend that other people do it too.
Do yourself and your passenger a favor and ignore any attempts to convince you to do what you most certainly know is wrong. Do not downgrade the tires.
Jerry