I would like suggest you the read fundamental of electronic structure
posted from Sudirman.
Please read the Clar's book in the English Edition.
When you write Clar's model, what a kind of P.A. H are you meaning?
I send you the source and a copy of the 2 pages about UV-Vis of various PAH (Annelation)(unfortunately in German) .
You can see that the peak wavelenghts tend to be shifted toward the long wavelenght region as the conjugated system is going larger.
Please read , according to Sudirman, the fundamental of electronic structure (Wikipedia, Chemistry books and physical chemistry books and fundamental of UV-Vis.)
After these readings you will be able to understand the big lot of papers about the relation ship.