front rear windshields on 68 charger

[charger2fast4u]

i bought a new ppg front windshield and a year one windshield gasket. it leaks at the corners is there a way i can fix it suppposedly the ppg windshields are thinner so the gasket won't seal it any fixes for this and where could i get a new rear windshield i got one from ps auto glass i got one from them acouple months ago and it has all these round dots and has all these different colors on it like oil gets when in water