Metallic control in blend areas is for sure a separate issue than the actual flop/sidetone of a sprayout panel. We have to make sure that we're all speaking the same language! Now I am not sure what @jcclark is talking about, since in the OP there is just a reference to "flop" without indication of whether it's light, or dark.Guys, I'm not trying to be a jerk so please don't be offended. Just to be the contrarian on the forum, in all my years of collision repair, I almost never did a drop coat nor did I do any technique other than standard blending techniques. Almost never did I have any flop issues. Then only times that I did, was trying to blend a color to a low grade basecoat, or using a low grade basecoat (not all the time by any means though). The techniques that AAE is talking about are about metallic control rather than flop control. Not the same thing. There is a difference. All you can do with technique is metallic control. You can't change how it lays down flop wise. Sorry.
I know when I switched to Standox, I had to bump my spray pressure up a bit to become more consistent with the Standox color chips (not much to go by, btw) because many of my metallic colors were simply too dark, especially on the flop. If you do choose to spray with a bit higher pressure, you may also find yourself needing a slower reducer, If there is lots of crunchy dry spray out in your blend zones, your reducer is too slow!