@JohnC and @ludwigkempenaar
I had to experiment myself with correct breakpoints for all my devices. I have an iMac27", desktop pc, ipad and iphone 5. The website I have created after days of trying out different breakpoints seems to display fine on all devices. I didn't use different breakpoints for iMac and desktop pc, but instead pinned elements, objects and text so that they would display nicely with different monitor or browser window sizes.
Have a look at the website and resize the browser window from full screen to very narrow, check breaking points and correct display of contents. If this is what you were looking for and the breaking points suit your needs, I could prepare a hype template for you if you wish.
Breaking points are optimized for desktop, iPad 2 and iPhone 5.
Probably you know already, to preview the layout on the iPad and iPhone, you will need to install Hype Reflect on your mobile devices.