Here are a few things to consider. Plane the pith of the strip flat when preparing the rough strips. Inspect nodal areas for humps and dips, humps can be squeezed to a degree but dips require displacing by scalloping the back of the strips. After squeezing the node that node must be FLAT, often too little heat is used to make the strip compliant and the bump simply returns. Gently remove intermodal sweeps to help the strip nest in the forms. Inspect the strip in the form to ensure the node is sitting correctly or you will get a glue smile, not the smile you want. I know some builders are flattening the enamel side to help with these issues but I leave some of the natural curvature in the strip, I like the look. Whatever you decide it takes time to get the strips ready but the payoff is huge, less straightening, more accurate dimensioning and less visible glue lines. Take your time with each strip, plane each strip to a uniform dimension and have better looking rods to show for it.