When we replaced our radiator last week, the shop said they put in about 12 gallons, and that's what was on their bill. May be correct or not, but it's at least 10 gallons. After I ran the engine several short trips and got it good and warm, I added almost another gallon to get it back to full; suspect it had air in the lines, especially in the heater hoses.
Ours came with ethylene glycol (the greenish-yellow stuff). I think proplylene glycol is pink -- and supposed to be longer life. I use Prestone 50/50 pre-mix ethylene glycol/water to top off the tank. Supposedly you can use it to top off either type because it is supposed to mix. My radiator shop replaced the coolant when they changed the radiator with ethylene glycol and recommended the Prestone 50/50 premix to add to it.
Former Owner, 2006 36MDDS
2010 Arctic Fox 22GK Travel Trailer
2007 Toyota Tundra