How to truly gauge usable space in Greater Noida flats?

Honestly, buying a flat in Greater Noida is confusing me after our kids moved out. We need a manageable 2BHK around Malakpur Village, aiming for ₹80L-₹1Cr. This 'super area' vs 'carpet area' thing is really getting to me. We checked a project by The Hemisphere. Their 2BHK super area felt inflated. It makes the per sqft price seem lower, but you're paying for common space you won't use. It feels like a trap finding true usable size for a smaller place. How do you compare deals honestly? What percentage difference between super and carpet area should one expect? Any tips on negotiating actual usable space before committing? Would love to hear your experiences.