We use Halon... Bottles reside in the Drivers area.
Two Bottles... a 10lb that actually has 11 in it and a 5lb that is 5.5.
The small bottle is drivers compartment only with a single very small outlet. Through a bit of bad luck we found out the small bottle will spray for more than 90 seconds. Expensive lesson. Always consider the size of the area to determine what is best for you. Our spray systems were sized by Jim Diest having us weld up nozzles to limit how much agent was released. When a driver is in there the amount of space left over is measured in cubic inches not feet....
OK, it is probably a couple of cubic feet total.
The big bottle also has a single small, about 1/16 inch, hole that releases into the drivers compartment as well as plumbing through the firewall for the 2 engine nozzles.
Having the big bottle split increases driver protection time. Don Vesco gave us good advice years ago... the driver is the part you should protect the most... and if you see smoke and think you are on fire... you aren't... you will know when you are on fire!
Good Luck with your project... have we seen pictures? lately?