Hi,
You can’t really modify the device pixels per inch on a display. I guess the plugin is a little misleading. The best way to view the heat maps for different devices is to use the actual devices itself. In the future I will try and add more information in the heat map data to be able to tell which device it is based on the user agent such as iPad or iPhone for example.
For device emulators see here for Android: https://developer.android.com/tools/help/emulator.html
Here’s a tutorial on how to view your website on an Android device emulator: https://sangatpedas.com/android-device-emulator-testing-your-mobile-site-on-any-android-device/
This also looks good but it has a cost https://www.manymo.com/.
Note your website will likely appear differently if a device has different pixel ratio (device pixels compared to web page CSS pixels). Images may be better or less quality, text may be larger or smaller, images may be different size widths and heights etc…
Daniel.