I went to a local block maker and asked what aggregate they are using . I then went to a local sand supplier and asked for 5 cubic to be deliverd . I had to order 5 cubic as that was the minimum I could order.
You mix 4 aggregate and one of cement . Pack in well into the two part mold , turn upside down and lift up . Long as you mix without too much water the block will hold together . Lay on a flat surface.
I could make 25 blocks in a few hours work.
I can send you a photo of the mold i made if you wish.