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Looking at the posted link it appears the minimum gain is 20 when nothing is connected between 1 and 8.
If you connect a 10 uF ( i think they recommend 0.1 to 10 Uf) capacitor only across 1 and 8 you will get the max gain of 200 but you may have problems with oscillations, this is why its sugested that you connect a resistor in series with it.
In the 386 amps ive built i used a 1 K variable pot in series with a 10 uF capacitor this gives very good control over the gain. Another good idea is to connect a 100 Uf ,with a 0.1 Uf capacitor in parallel, between pin 6 and ground, this will help prevent oscillation as well.