Hardware SPI with Mega2560 + WS2812 + FastSPI_LED2

Hi, it´s a problem with a Mega2560 + 240 LEDs WS2812 using the lib FastSPI_LED2.

So far I get it working with this initialisation using pin 6 as dataline:

void setup(){
   FastLED.addLeds<WS2812, 6, GRB>(leds, NUM_LEDS);
}

It works, but is pretty slow.

Question 1: How has the init to look to use the Hardware SPI? Which pin is it then at the Mega?

Question 2: Is there somewhere any kind of documentation for the library? Like a list (+descripton?!) of all functions?

Thanks for any hint and help you can provide!

I know nothing about WS2812 and FastSPI_LED2, but Arduino Mega 2560 SPI is described here:

MOSI(SDA): 51 or ICSP-4
MISO: 50 or ICSP-1
SCK(SCLK): 52 or ICSP-3
SS(CS): 53

The WS2812B is a slow chipset - it's an 800khz data rate, and there's really no speeding it up (without parallelizing the output, which i'm working on for arm based platforms, but unlikely on the AVR) - it's 30µs per led, which means writing out a frame is going to take you 7ms.