Double Staffs Tips
Doubles are usually shorter than a usual staff. Between approximately 3' (~1m) and 4'(~1.2m). Though some use two normal length staffs for doubles, it is a matter of preference and what moves you wish to perform.
Short doubles are great for doing tricks between your outstretched arms, which allows for a greatier variety of tech.
Smaller diameter tubes will allow for finger spinning.
It can be helpful to start off with a staff that has different color ends. This will help you identify the movement of your staffs and determine if you are doing tricks right.