welcome to ReefBase
As you say, stretching usually means too little light.
Your settings look fine, you could bump up the blues and violets into the HD range to increase PAR a little. Also you could increase the duration, which looks pretty short.
The other thing you can do is to lower the lights, raise the zoas in the tank, and make sure the water is clear (put some tank water in a white bucket and see if it looks yellow). If it does look tinted, you can change your activated carbon, skim, run a fine filter floss, use coral snow (let me know if you want the recipe) etc.
edit: forgot to say, I have some zoas which stretch even right under a Hydra 26HD at full blast. I think it's just how some zoas are, especially the big ones like ARC Woodstock (might be palys rather than zoas in reality)