Nice work. Im used to seeing a lot of really crappy craftsmanship, it's refreshing to see something turn out professional every now and then.
After you get a little organically grown goodness in your hand, your smoking habits might increase slightly...
Keep it up!
Get a couple of runs under your belt. You'll eventually decide to modify your blurple lights into COBs and you will then have a bit of experience. I'll help you choose what you'll need for the conversion whenever you're ready.
Temperatures are going to dictate what your fan speed is going to be. My upper canopy temps can sometimes reach maybe 82 degrees, but the entire cabinet, measured at the top of the cabinet, never goes above 75. Do you have a small fan inside stirring the air in the cabinet? If not, you should...
Fan for what? In that space, I'd have a fan pulling air through the carbon scrubber and a fan stirring the air in the box. No intake fan, passive intake. I like the Noctua fans. Very quiet. Whatever size and RPM you want as long as it moves air. 20 CFM should suffice.
The lighting you described...
Popping a dozen seeds is a waste if you only want 1. There is no way to tell which one would have the least odor.
The fan will be quieter if you mount it on rubber mounts or suspend it from straps. Use flexible rubber hose to minimize any harmonics. I'm growing a skunk strain at the moment and...
You accidentally did what's called the "gas lantern routine". Supposedly a way to keep them in veg without using as much electricity. Watch the trichs.
Still requiring an upgrade for everyone who wants to stay with the most efficient chips. I'm going to be running my vero 18s until they pop before replacing them. Same goes for my 29s and V22s. It will be interesting to see how current prices on older chips will be affected.
I have about 250 into it with 2 passive heatsinks and a potentiometer so a little over a buck a watt for my build but it could be done cheaper. It's going in an area of barely over 3 square feet so the dimmer is almost mandatory for me.
Getting a bigger pot and not completely filling it also has the added advantage of being able to be topdressed in the future if needed. I've topped with earth worm castings about halfway through flower with great results.