The best reviewed product that I've seen so far for keeping the red color of cedar shingles is Penofin brand. Haven't used it myself but all the online reviews I've read indicate that it will help keep the red color longer although most everyone's review indicates there is some fading. It's not cheap stuff and has to be reapplied periodically. Good luck!

+1 on the Penofin recommendation. The guy that installed our fence used it on cedar planks, and three years later they look just like the day they were installed. Areas with thinner coverage have faded a bit.

Posting pictures would certainly help...

This is prior to finishing

If I were you i'd be putting a rainscreen under those shingles.