When leeching problem on shootout clones came out, I thought that the problem was leeching and not infinite leeching. With your solution you will have only temporarily leeching but you'll have it. In many games leeching has been banned and many players had their score lowered. I don' t know why we had to permit it. Avoiding to leech you can do about 200-300k (for now), considering a leeching of about 250k (you say that this is the maximum leeching possible) you will double your score. I think that this is not right. The correct settings for me are : 3 mans bonus at 70k (Initially I thought that bonus was on 20k,70k,170k ecc. (I don' t know why but I thought that) difficulty medium(posted 9328 days ago)Substantially I prefer to use 3 mans and a medium difficulty.
P.s. In pre roller coaster stage you can get 25-30k (probably you don' t know that you can hit the barrel on the left to obtain 200 points) and not 15k as you said. After all I don' t know "If you know exactly what you' re talking about". ;)