I'm a new diesel owner--2005 GMC 3500 4X4 Duramax 6600--and wish to know which fuel Conditioner/Additive is recommended/best. Saw my dealer today and it was suggested I use the 'World Blend' Lubricity Formula from Standyne--one pint/470 ml treats 470 litres of fuel. Any suggestions or recommendations would be appreciated. Thanks.