hi
you can put the boomerang almost flat but the balls dont run out again, and the hight can be ajusted, i think its not so much about putting the ball in the cup but hitting it so it stays there, there is not a big lip in the boomerang so the pace of the ball has to be right, the same when hitting the second ball you hit it just a little harder,
you have to get the feel for the right pase for the ball to stay, other putting mats you can hit the ball hard and still hole it that where with this there more touch needed. one thing i do it hit the first ball from about 8 feet and the second from about 5 feet, then change, first ball 5 foot and the knock out ball from 8 foot, i try and change the distance to the hole. it makes it harder.
i realy feel that after using this for a few months i felt like i could not miss on the couse from 6 foot and i was shocked if i did miss as i got really good at putting, i do think changing to a broomhandled putter help too.
before i was not a good putter of the ball and 3 putted 2/3 times a round, now its rare if i 3 putt in a round.
bill