Always set the encryption of cloud backups and local backup directly to AES 256 Bit. While this strong encryption requires slightly more computing power, it guarantees maximum security. Set a long, secure password and print one or two copies of this password. Place these copies in a safe or bank safety deposit box. Before storing the password, verify its correctness by performing a backup restoration test.
Nerd Info about AES 256 Bit (as of 10/12/2018):
The secret key can be found in 2^126.1 steps for AES-128, in 2^189.7 steps for AES-192, and in 2^254.4 steps for AES-256. With current computers, this corresponds to computing times ranging from several dozen million to several hundred million years until the password can be cracked by brute force. For this reason, the AES method is considered secure and is standard in many government agencies, institutions, military organizations, and banks. Source: Wikipedia