I just posted a review on CarPro CeriGlass
that might help you. Review: CarPro CeriGlass
For the last few years I've applied Aquapel as a glass sealant to my glass with tremendous results and satisfaction. It's on sale currently for $7.99 and for 6 months os solid protection how can you go wrong.
This year I decided to give Gtechniq G1 Clear Vision Smart Glass
a try and see how it compares to Aquapel.
Gtechniq G1 Clear Vision Smart Glass out of the gate is 3X the cost and it a little more time consuming to apply but the proof will be clarity and long term durability. Wax
The Klasse "twins" were formulated to work together. This doesn't mean they can't be used independently because I have many times. Klasse High Gloss Paint Sealant provides tremendous protection and two coats is probably as good as it gets.
The addition of Collinite 845 will add depth and additional protection but to what degree is up to you...