How much money should I invest (what percent%) in already proven mobile marketing methods and how much in new methods? As in order to increase conversions I must try new methods every now and then.
I suggest you split your budget to 80-20. 80% for already proven methods and 20% for experimentation on new methods.
Split it according to your need. 85-15% is good enough in general sense. Spend the most in already proven methods to certain your profit.
Split them into half. I would suggest this because in this way you will have enough field to play with both of them.
Give much attention to the proven methods. New methods for experimenting are also welcomed but if don't make any profit then there will be no money soon to experiment or to make profit.