When it comes to cutting a dado, nothing beats a stacked dado blade set. Like other dado blade sets, mine comes with a 1/32" chipper (in addition to the standard 1/16" chipper). This gives me a lot of choice when it comes to "tweaking" the fit of a dado. Especially when cutting dadoes to accept "off-size" thicknesses of plywood.
The problem is it takes awhile to find the exact combination of chippers needed to produce a good fit. So I use this handy gauge to tell me at a glance, which chippers to use, see drawing. The gauge is nothing more than two glued-up pieces of ¾"-thick plywood with a series of dadoes cut in it - one for each different width of dado that I can cut with my blade. The combination of chippers required to cut each dado are labelled underneath. Using the gauge couldn't be easier. Simply test fit the plywood (or other work piece) in each dado until you find the one that produces the best fit, see photo. Then read the label to get the right combination of chippers.
Ted's Woodworking - Guide eBook