Note that how unbalanced you can make it depends on the stepsize of the high-capacity pipe. With the ultimet pipe, with a stepsize of 2k vs 32k for the brass pipe, 16 ultimet pipes is equal to 1 brass pipe in length. However, a huge brass pipe with stepsize 8k is only equivalent to 4 normal brass pipes.
EDIT: Also, if you want to save materials on the higher-capacity pipes, you can instead have one-length brass pipes going into hoppers, which connects to the ultimate destinations. That way the possible paths still only have one brass pipe.