Is there a recommended way to do Ektron wireframe template migrations?

We have several thousand content pages using about a dozen or so custom templates that were created in-house over the years. Recently we've created three new templates and would like to migrate all of our exsiting page content to use the new templates. Is there a proper way to do this in automatically / programmatically?

Currently we're investigating bulk migrations via SQL (direct) or via a Console app but I'm hoping there's a better way.

Suggestions?

Using 8.50 SP2(Build 8.5.0.356) --- old version, I know