Powerservice White Bottle for the winter time months. Powerservice Grey for the summer. Some will say use it with every tank and others wont. I use it when I remember to use it. Say every 3rd or 4th tank. Good security for your fuel from freezing up in the winter. White bottle will boost you cetane number by 4 and the grey by 6. I also see a little better MPG using them. Say 1-2. I also like to use it for the lubrication properties.

As for the brake question. Not sure on the integrated system. I have my brake controller at 35-40 when towing my TT (6000). But I also have mine at 10-15 with my flat bed trailer on empty and bump it up to 25 with a load. It varies from trailer to trailer. Does the integrated brake controller have a syn mode that delays the brakes on the trailer? I would assume it does. The 5.0 is the middle of the road of 1-10. At least that is what I think. Mine reads 00-100.