If youre going to use HID, just make it easy on yourself and use 2x 1000w Hortilux HPS.
Ive used them from seedling stage through flowering for almost 30 years.
A 600w HID, with the highest PAR bulb ( Hortilux ) covers a 3 x 3 area/9 sq/ft. 3 of them will cover a 9 x 3 area. 27 sq/ft. You have 32 sq/ft. Leaving you 5 sq/ft short.
If you use different wattages, youre also going to have them at different heights. You will have to have a 315w CMH much closer than the 600w HID
For maximum production you need 62.5w Sq/ft of HID. Hortilux make probably the best bulb available for a 4 x 4 area. A 1000w HID has always been recommended for a 4 x 4 area.
Ushio does make a bulb thats more powerful, and can be used in a 5 x 5 area. Its 2100umol. Hortilux is 1880. But after 1 month all HID except DE lose about 10%. This is a stabilization period. Ushio must be run 36-40 inches from canopy.
DE HID does not lose 10% the first month, but are extremely hot, and need good cooling, and either CO2 enrichment, or airflow like your outside, or the plants simply wont be able to use all the umol. The Ushio will also run hotter vs SE Hortilux.
1000w HID is good for a 4 x 4 area. And is the industry standard. 4 x 8 area would need 2 of them.
A 600w HID is good for a 3 x 3 area, you need to cover 4 x 8
A 315w CMH is only good for a roughly 4.9 sq/ft, 2.2 x 2.2 sq/ft area. You would need at least 3 of them to cover a 4 x 4 area to equal a 1000w Hortilux. 4 315w CMH in a 4 x 4 would be better and more evenly covered. Using 4 of them would only be .8 sq/ft over the recommended coverage area.
A 600w HID in a 3 x 3 area is 66w sq.ft.
A 400w Hortilux has slightly more than 1/6 more umol per second than a 315w CMH. CMH may run a bit cooler.
A 315w CMH has 598 umol per second.
A 400w HPS/Hortilux has 713umol per second.
If you want to add UVA/B use 2x 32w Solacure 4ft Flower Power bulbs per 1000w HID. You would need 4 of them for a 4 x 8 area, and run tem about 4 hours a day
Most dont do it, but run UVA/B from Seedling stage, all the way through flowering. I also start seedling under 1000w HID, and have for more than 40 years. I figurre they get blasted at the equator from day one, so why not inside too?? And they also get UVA/B from day one outside, I add UVA/B for that one simple reason. Also adding it in the last stages of flowering can ither stress them, or fry them because they arent used to UVA/B. Its like setting an indoor plant in full sun. It can get fried to a crisp.
I run my UVA/B bulbs 5 hours a day at a height of 20-24 inches in flowering, and 24 inches from seedling-veg. Recommended is at least 2 hours a day. To much UVA/B can reduce yield 5%-15% but increase trichome production by alot.
