Is it possible that the Hotspot version will ever contain a comprehensive catalog, or would that dig into sales of the main product? Could you add a back-catalog to Hotspot without impacting sales?
Can you handle phones with moving parts? e.g. QWERTY sliders like the Xperia Mini Pro, or addons like "Moto Mods" or the Essential PH-1 360 Camera.
Are you in discussion with any of these "websites that let you compare the specs of phones"? That sounds like a great match.
1.5MB sounds a bit large when most phones have quite simple geometry. Where does the file size come from?