Peter, would you mind elaborating on why a bulk rise is not recommended for a cold ferment?
The only purpose of a bulk rise is to maximize the dough's internal thermal efficiency due to the larger mass to surface area (thermal interface) ratio. In other words, when the yeast produce heat as a byproduct in the dough, the mass of dough with the smallest surface area will lose the least amount of heat over time. Once you ball the dough, you increase the heat exchange rate through an increase in surface area. This isn't a critical factor in fermentation when the yeast are in an environment that falls within normal (comfortable) functioning temperatures such as room temperatures (e.g. 68-77°F). It does become a critical factor when you place the yeast in an environment that is not optimized for their physiology, such as a cold refrigerator.
The point being, in any instance where you place something, anything, in a temperature controlled environment, you obviously want that something to reach the controlled temperature. Placing a bulk mass of dough in the refrigerator is counterproductive to that end.
Also why does the cold ferment use more yeast?
The desired amount of yeast is not a result of temperature function; rather it is a result of time-dependent net activity. Restated from above, yeast do not function optimally in a cold environment (the same as most organisms on planet earth). Therefore to compensate for their lower activity over a predetermined time, more yeast are used to perform the same net activity as yeast in an optimal (warmer) environment for that same predetermined time. However, if the time at two comparative activity levels is not the same, it may not be desired to increase the amount of yeast operating at a lower activity when such activity takes place over a longer period of time.