If I understand you right, you want to register a domain name elsewhere other than with DH, but still have it hosted with DH? If yes, then as long as the domain name is pointed at DH's nameservers, then it'll work. IE: you can register through anything like godaddie or whoever you choose, so long as the registrar knows the information it needs is held on DH's nameservers.
You can set up your own DNS to point to your DH server's IP address if you want to, but that isn't as reliable, as your IP address may not remain the same. If they have to change their network topography any, or move you to another server, then your DNS will be broken until you update it manually, which needs another 24 hours or there abouts to propigate.
Yes, I have an opinion.
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