How does different diffraction grating effect resolution and sharpness of lines in a line spectrum?
Sharpness is colloquial for how narrow a peak is. Resolution is how well we can see two features as they move closer together. You might do well to re-read your book to learn these definitions better. As already noted, skinnier and more clear have no meaning in spectroscopy.

A search on terms such as diffraction grating equation will give you further reading to support or invalidate the guess (hypothesis) that you propose.