No one can tell you what you should set it as - it differs from chip to chip. However, the max safe limit is 1.4 V, 1.45 V on good cooling.
To find what you should set it at, you'll just need to keep bumping up clock speed gradually, until the PC becomes unstable. Then, bump up the voltage until it becomes stable again. Then, again increase the clock speed until it becomes unstable, and again bump the voltage until it becomes stable again. Repeat this until you reach the max voltage you'd want to run the CPU at. Don't exceed 1.45 V, and 1.35-1.4 V is usually okay.
https://linustechtips.com/main/topic/777611-ryzen-5-1600-overclock/
^This guy hit 3.7 at 1.3 V, but it's not necessary you'll have the same results. Your CPU might be stable at 1.25 V, or it may need 1.33 V to run at 3.7. Which is why you need to test yourself, since each CPU has unique OC capability.