I am trying to create a very simple RWD Template. I have searched and unable to find the most suitable max and min widths which will be ideal for the plethora of current screen sizes.
Stop chasing your tail and forget about specific devices. The only breakpoints you need are the one that your design needs. Nothing else matters.
Don’t design for specific devices at all.
The problem with all frameworks is that they set arbitrary breakpoints that have nothing to do with the design in hand and assume that devices haven’t changed (they have - there are thousands of them now all at different widths).
All you need do is create a fluid layout and then when your design looks awkward or doesn’t fit then throw in a media query and make it look better. With a few well chosen media queries (and loads of dragging the browser window open and close) you will automatically cater for all devices.
I follow this concept on all sites I do these days and it works well (even with new devices appearing all the time).
It’s pretty accurate but by no means should it be a one-size-fits-all. If the media queries don’t match where specific elements are breaking, then you need to actually make new ones. ALthough you really shouldn’t need more than a few media queries if your page is truly fluid. If you have as many media query rules as you do regular CSS, then you almost definitely screwed up big time.