Does anyone know what brush spring combo works best ?

I don't know what you run, but I have good results w/ xxx brushes with 1/10,000 shaved off trailing edge and red/green or red/red springs. The brushes will last a long time and won't fade during that time.
I"m running 5 minute races. Using reedy 766 brushes and the stock springs.Also do you
mean trinity XXX Laydown silver stock brush and what springs (trinity) ? THANK YOU.