I will build my one , with Texas Avenger boards . I use the 22mm boards , with LDO : Texas Avenger "TA" Driver series - Triple channel + Bistro or Narsil + Clicky or E-switch - The Ultimate open source driver!
One main reason was Narsil it self , i really like it .
In series the same current would go through all of the leds , total current will be equal to the current of each one xhp70 .
In parallel , if total current is 30 amps , it will be distributed equally , 10 amps to each led .
For a build like that , you need to mod stock driver (probably a resistor mod) , or use a fet driver (leds in parallel , current will be as high as batteries can give , and leds’ Vf allow ) .