Hi, I am from Singapore and I follow your channel, I am a professional in building carpentry and formwork, ask you dad to mark a permanent laser line along the perimeter of the site just hammer many stick around the site and copy the laser line using black marker so in bright sunny day you still can use the line now what is needed is one stick in the middle and attach a thread on top which is the laser height so if needs to take level reading just pull the thread to the side of the marker, green laser is better the red but large area the light is weak, hope this help and hope everything is good for everyone working there.