When you are not sure about the coupling strength between orthogonal lines, you need to use basic crosstalk simulation software to check the vertical leads to see if the crosstalk between them is within the noise tolerance range. At this point, you need to plan the signal return path, which is a major problem in vertical routing. This is a classic “do/avoid” rule that is often debated. Some PCB designers say they never use heat-prevention vias and have never had problems with soldering and assembly. Another group insists that thermal vias need to be used whenever each plane is connected. Who are they right?