I had Krators on my Street, and I swear by 'em, they made all the difference. On my new bike it had the exact same mirror issue; I immediately traded out the stock mirrors for the same long-stem tapered mirrors I had on the Street, but even then, it's not enough and I found that I needed Krator-style mirror extenders.
I looked on Amazon, they're going for about $38 now. But Google Shopping brought up an alternative, some site called "banggood.com" that offered what looks like exactly the same product,
for the absurdly low price of $11.49, and that included shipping!
I just received the package today; will install tomorrow. Looks to me to be basically the exact same thing as the Krators.
For anyone going this way (Krator or banggood or whatever), I'd recommend swapping out the flat washers that come in the kit, for lockwashers like the genuine Harley kit has. Lockwashers make a big difference; with the flat washers I'd find that my mirrors would loosen up, but the lockwashers fixed that.