@Matt. resistors can be around 1/4watt but if they're above or below (1/2Watt, 1/8watt) it doesn't matter. The most common resistors have a tolerance of  5%. you can use 1% if you want although there will likely not be any real difference. There aren't any polarized capacitors so cap voltage ratings aren't really an issue.. small value (non polarized) caps usually have a high voltage rating far above the power supply of the benjolin.