Best way of switching between different resistor/capacitor values in a layout?
I am not so certain that there is a generic "best way" to choose between component selections. There may be a best way for your specific application and only you can determine what works for you. That said, there a multitude of ways that this can be done. Here are a few examples:

rotary switch



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dip switch



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header with jumpers



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alligator clips



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analog switch



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digipot



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decade capacitor



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fahnestock clip



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mechanical relay



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soldering



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