A good novel idea but 3 months time frame is too short, 12 months is more ideal.
Let us avoid a repeat of the past that is intelligent investors boxing themselves to a tight corner because of their predictions and disappearing from the scene unceremoniously. witty analysts like Jammo, Tuscar Baridi and many others are out of the scene for obvious reasons.
Beyond TA and other fundamentals, there are several external factors that can impact negatively or positively on a stock (govt policies, political climate, profit warnings etc), therefore it more ideal to give a longer time horizon.
Also NOBODY should be invited to participate, let interested members VOLUNTARILY offer themselves to "play".
The wazua spirit as members is to educate and inform and learn from others within the limit of what we know in any chosen area irrespective of our differences in tribes, nationalities, etc. .