Rear coil springs are SHOT! Replacement Question???

[Blue Baby]

HELP! The rear coil springs on my truck are collapsed like a bad lung. Is there a way to measure the spring to see about how much the truck is "lowered" because of the bad springs??? The reason I ask is because I'm about to lower it for real and don't want to buy lowering springs only to find out that it has the same ride height and my old worn out ones. I'm going to lower the front 3 inches and would like a slight rake. The three middle coils touch, that's how bad they are. Any ideas on guessing what lower springs I should buy???