I never got the front drum conversion thing. Its such a quantum leap backwards. They are heavy and reduce the compliance of the suspension. You score points for looks, but a well set up front end with period iron discs and AP calipers looks even better and stops far better as well. In the day before there were good disc options, then OK, but now you can have better period stopping performance for similar money. Suzuki hubs aren't falling from the sky and the rest are far more expensive than that.
As to the rear, both the stock drum and disc were tremendously overpowered for the task, easily locking the rear wheel. The best rear brake is one you can all but stomp on and not lock the rear wheel. Realistically there is no reason to even use the rear brake, especially on the street unless you are a very aggressive rider and ride to the edge of the bikes ability.