I use my flashes with 43" umbrellas, 33" umbrellas, and 23" umbrellas--all with good results (although you could certainly use a 60" umbrella, too). However, the larger the surface of the umbrella, the softer the light will be. A 33" umbrella's results will be a little bit "punchier" than the 43" umbrella's light.


When it comes to reflectors, bigger is not necessarily better. Many large reflectors tend to pancake with light wind (and simply from the force of gravity if they aren't very rigid. While in theory they can cover more area (and in practice, a good one can, in little wind), smaller reflectors tend to be easier to handle and fair better in the wind. Also, the triangular ones with handles make positioning the reflector very easy (assuming you have someone to hold it).