To be honest, I think Ala Mihgo is just fine for practicing your new Level 70 skills and rotation.

If you do it via Duty Finder, you are probably guaranteed to get a squad of experienced players. As long as you put forth a reasonable effort, most players won't complain too badly, especially if they're getting an easy WT Second Chance out of it. It shouldn't take that long for you to get the hang of it.

And you can also ask if anybody has experience with that job and could tell you how you should deal with your new Lv70 skill. There's surely some peeps around that could help you out with a quick cliffnotes as to where/how your Lv70 skill fits in.