Brake Disc Grooves.

[wixer]

I'm currently renovating the whole of my suspension and brakes on my Griff 500 and as there isn't much wear on the brake discs I'm just going to have them re-faced. Whilst they are in the machine shop, I'm tempted to get them either cross drilled or grooved. Does anyone on here have any technical knowledge on the ideal amount, shape, depth and profile the groove's should be ?? Or does anyone know of a site where I can find this detail out ??

Thanks in advance.