I think your method is the simplest possible and will work all right.
Of course, if you had strict specification to follow, you could need to back-extract the alkaline layer to eliminate possible traces of naphthalene, but this sounds much like a didactic experiment.
If I may give you a personal advice, be more confident in your approach: as long as you rationalise every step, use the literature when required and don't make (too many) arbitrary assumptions, you don't need any 'superior' or 'professor' to tell you that you're right.
Your only 'judge' is nature, and that's what science is all about.
Sorry, too much philosophy here...