VeraCrypt is free open-source disk encryption software for Windows, Mac OS X and Linux. In case an attacker forces you to reveal the password, VeraCrypt provides plausible deniability. In contrast to file encryption, data encryption performed by VeraCrypt is real-time (on-the-fly), automatic...
You shouln't have any issues. The hidden volume already takes up space, so in the worst scenario, you won't be able to resize the partition if there's no enough space.