After several plays and I have to say we always won but with some stress in some adventures I created some custom rules:
1- Max number of Clue Tokens: 5 per investigator. 2- Max number of cards: 3 of each type per ivestigator. 3- You can only buy one Elder Sign token (10 treasures) per investigator in a single game. 4- Place the monster in order starting from top leftmost empty or monster space available adventure card. Respect 1 monster per card before assign a second one.