DWC/Bubbleponics Reservoir

Hey there RIU! I've decided to try something new this year and go with bubbleponics since it's something I've been eyeing for a while now.
I have a 39 gallon sterlite tub that I can use as a reservoir. I wanted to use this one instead of going out and buying a 5 gallon sterlite tub.
My question here is if I use a 39 gallon tub how much water would I need to fill it with, can 8 plants fit, and can I still follow roseman's guide with this tub?
Here are pics just incase...

thanks in advance for the help.
-RollingDope

Go check out my set up its simpler

I saw it. I'm trying to do something without transporting them and it's not a micro grow.
However they do look good starting off

If you want check out my 1st grow and my two ongoing ones
https://www.rollitup.org/grow-journals/712625-rollingdopes-la-confidential-bagseed-cfl.html

https://www.rollitup.org/grow-journals/755936-rollingdopes-auto-northern-lights-cfl.html

8 plants might be a bit much. I would think maybe 6 might be a little safer, but personally it's easier for me to get more weight off of fewer bigger plants than more small plants. That, and I haven't seen the size of your space, and I run aeroponics so I can't speak for dwc. But the growth is crazy fast with aero/hydro, so I would probably keep the number smaller and veg a little longer for full colas.