I'm weaving a 2/2 twill, I thought that would balance the colours and black best. After weaving the first inch or so I'm not sure if it will end up to black and mute the colours to much.
Update after some more weaving, I'm happy with the result after all. I'll happily continue with the 2/2 twill.
Advantage with 2/2 twill on this warp is that both sides look the same. With 3/1 twill, one side would look really colourful but the other side will be very black with 1/3 twill. So, I'll stay with the 2/2 twill on this warp.