2x4 grow tent setup

figured id go into more detail regarding my choices so far. as far as the lights go i had thought it would be a near perfect spread considering there dimension and the fact they are only 3in tall with from what i "hear" runs fairly cool.

the 8in and 6.5 in listed in the picture below is the spacing between the tent and the light itself

And for wanting the flood and drain, I’m just looking for a little automation. Being there may be times when I may not be home for a day & would like to know the girls get watered. I figure losing 4-5in is a fair trade off for the reassurance. And being that the tent is only 5ft it gives me a little head room to elevate the tent to help getting the flood table above the reservoir. is there more ideal pots that are perhaps shorter and wider?

Mounting of the fan and filter will be in the back side of the tent and should still allow the light to be raised nearly flush to the side of the fan/filter being the light is only 8in wide itself.

and with the available space I intend to try my hand at trying the “flux” training method as I can see it suiting this space, I’m not looking for any major weight as its just personal for myself. That being said I’d still like my tent to be as efficient as possible.

The first round I’m sure won’t be ideal until I keep a cutting off one of the girls and start by clone for a mono crop with uniformity, so I very well may just sog it the first round in order to find a keeper. Pictures below are examples of said flux training method and are not of my own.

"Happy 420 guy" on youtube has a nice time lapse video series on the training method

I cant see your pics but with a 2x4 you will be very happy with the HLG260w kit. They are very intense. I have a couple of them.
The 4" fan will work fine. But a bigger fan on a slowed right down will be quieter so depends on how much noise you can tolerate, even silent fans are loud.

Plant count is good too.

Coco is a good choice but not the best option for flood and drain which involves recirculating nutrients.
Clay balls is a good choice or grow stones even better for flood and drain. Coco would be better for drain to waste drip fed or hand watered

I would go with the 320 kit when it's cold out those extra watts will help you warm the tent up you want to be at 80f 4" fan is plenty for that size tent. Canna is good but Coco blends that have some peralite have worked better for me. If your doing 2 plants I would just use 5gal pots you won't have to water every day

Here is everything I had for my 2x4 tent:
https://growpotma.wordpress.com/2018/03/28/the-500-grow-tent-everything-you-need-to-harvest-a-half-pound/

Here is everything I have for my current setup:
https://growpotma.wordpress.com/2018/03/30/the-perfect-grow-room-setup-how-to-harvest-a-pound-every-month/

It seems like you're going for a more complex setup but I thought I would share! I help my friend out who has a setup REALLY similar to what you listed and his plants grow a little faster, not by that much though. In my opinion its not worth spending 3x-5x as much time and money for your plants to grow 10-20% faster, but he loves the complexities of hit setup. He likes playing mad scientist I always say lol, just from reading your post I can tell you are similar. I always try to encourage beginners to start out with a cheap simple setup but it seems like you've done your research and will have success either way. Good luck!