Board Thread:Questions and Answers/@comment-33273295-20171006170128/@comment-33728484-20171022141907

If you don't want to save the Elder Kais for characters that you might pull in the future, then you can use them on Gogeta, why not.

The sooner you dokkan awaken Gogeta, the sooner you'll be able to bring out the full potential from his pairing with SSJ3 Vegeta. But even without that, SSJ3 Vegeta can still tank, and if you keep SSJ4 Goku next to SSJ Goku GT he'll beat the Gogeta event very easily. So I agree with Ndxtg, you can start using Super STR right away.