Hi there!
So you have awesome one hand navigation, but what happens if you like to open up other tabs while browsing?
For example, if you tap and hold a link or picture it opens up a menu, but that menu is waaayyyy above the standard thumb area, so I'm forced to hold the phone a certain way.
What would be cool, is if some buttons popped up with a few circular icon buttons (eg a plus for new tab?), perhaps I don't even have to life my thumb to slide to one of the buttons?
I know this is unrelated, but another idea you could do is have an option to hold the back button to bring up main quick button? (Or tap and hold in a spot to bring up the menu talked about before but has a button to bring up standard menu?)
Have a good day!