You sir have saved my day and a lot of further headaches! Thank you so much, yep, one of the cobs was in the wrong way around (don't I feel silly now).
As it stands, light and dimmer are both working. Thank you so much.
I've got (my first attempt) an AK Auto, Honeysuckle, and Icebreaker seedlings growing. They're all currently under 100w cob which I switched from a T5 last night. Each plant has 3 or 4 nodes.
Soon, I'll be moving the AK Auto and Honeysuckle into their own 2x2 space with 200W Cree cob, and will leave the Icebreaker under 100W Cree cob. I hope I've timed it right, but, I'm thinking I can harvest the AK Auto right before I start to scrog the Honeysuckle (around wk2 of flower).