Really it's easy with redirect.center
If you want create a CNAME as :
www.proof.com IN CNAME www.proof-two.com/path/index.htm
using redirect.center your CNAME look as canonical mode as:
www.proof.com IN CNAME www.proof-two.com.opts-slash.path.opts-slash.index.htm.redirect.center.
Now if you want redirect to https website you can add this option:
www.proof.com IN CNAME www.proof-two.com.opts-slash.path.opts-slash.index.htm.opts-https.redirect.center.
Now you can create a CNAME with the canonical mode with slash in your destiny page.