First grow. 315 CMH and auto flower questions

So I started my first official grow a couple of weeks ago. Started with 6 seedling 3 sour diesel haze autos and 3 amnesia haze autos. One of the amnesias didn't make it out so my original plan to run 3 2gals went out the door so I swapped to 3 gals to make up for the loss of one plant. I'm kind of worried my one Phantom 315 isn't going to suffice but if I don't train at all I figured it would be alright. I'm also unsure of the feeding on autos so I've also included the feeding chart which recommends 1/2 strength nutes the entire lifecycle. I'm open to constructive criticism and guidance to bigger and better yields.

Specs
4x4
315 phantom CMH with Phillips bulb 3100k
5x3 gal auto pots
3 part general hydroponic nutes