Hi - just to add to this thread.
For TXT values
Do add a period at the end of the key (post 1)
Enclose Value in double quotes
Add new TXT
Strangely enough (for me) the RAW Zone file (at the bottom) reads
_amazonses.domain.co. 1800 IN TXT "LOng+Key"
and the entry reads
You can test your DigitalOcean DNS settings from the linux command line by doing this:
For TXT entries:
host -t txt _amazonses.domain.ext ns1.digitalocean.com
For CNAME entries:
host -t cname secrethash._domainkey.domain.ext ns1.digitalocean.com
Hope this helps some people.