(Grammar aside, trust me I'm not bright! I do have auto spell though. . .)
Something like this, at this idea stage, would be approx 5300G.
Especially at the drawing phase, you'll never make that 0.4 work!
In my opinion, that's far too much!
it's just too big!
Only once the actual shell is constructed and the drains are in, you could guess closer, even then, factor in substrate etc, you'll still be out by a few hundred G.
You'd still need to count them buckets in!
All you need is 1/2" of misplaced shuttering, that's going to cost 50-150g, or you'll gain that amount! (. . .and that's not even close! Just a wild guess)
I went from 1052 litres to 794 litres (paper to production)
Last fill 860 litres, substrate is the variable.
) u.s. gallons down to 210 odd. (According to google calc)
Scale that up! You'll be roughly 500gallons either way!
Really I'm fairly convinced this is just a pile of paper waiting for recycling, I'm not saying it's impossible, I just don't think you're quite ready!
But if you do ACTUALLY have the money and space, recruit some people!
Maybe 2-5 years of planning, you'll be good to go!