I find that locking the wheels is more down to surface conditions than the power of the brake. In particular I've managed some fun two wheel skids on wet cobbles on a 15+% hill where even the slightest pressure locks the wheels, keep staying upright and you're fine. It's worth noting that the coefficient of sliding friction is (always) less than the coefficient of static friction so skids stop you slower.

For motorbikes the rule of thumb for ideal braking with no skidding is 2/3 front and 1/3 rear braking power which I reckon is what I use mostly on a proper bike as well. On a motorbike this can be achieved nicely with twin front discs and a single rear (or a single disc and a drum) but for bicycle rim brakes it's easier just to pull harder with one hand than to fiddle with setting the leverage. For cycle disc brakes you could use a larger front disc than rear (or front disc and rear rim) to achieve the same effect.