just wanna share my experience with you..
I actually used to use those 3 combinations (clay bar, show car glaze, and hi tech yellow wax)
but since last year..I started to use klasse..I use the combination of klasse all in one and klasse high gloss sealant..it's an acrilic sealant not a carnauba based wax..
they provide more protection in exterme weather like in WI..especially during winter..and they provide at least 6 months protection..this I have proved it myself..the shine is not decreased during those 6 months (with regular washing of course)..
but anyway, I still have several bottles my meguiar's stuff in my cabinet..maybe I'll use them during the summer months (when I can polish and wax frequently)..or when I feel to do the "show car trick" by applying a canauba based wax (like zymol, meguira's hi tech yellow, etc.) on top of acrylic or polymer sealant (like klasse or zaino)..this will further enhance the shine IMO..