[PlayDoh]

Don’t skimp or get inventive with a heater. Dozens of people die every year from CO poisoning. It’s no joke.
The Buddy heaters have a ceramic burner and burn very clean. Personally I wouldn’t trust a sunflower.
I have a battery powered CO detector, That I hang from the tent pocket to try and be as safe as possible. I also go out and check on my tip-up or JJ every 30 mins.
I put tent heaters in the same category as winter tires, and things you don’t mess with. Get a quality product and don’t risk your or others lives saving a few bucks.
I got an adapter for $20 and can fill the 1 pound bottles from a 20 pounder. You have to learn how to do it properly, but I find it more practical than the long hose and adapter. I have a long hose and kept the 20 pounder in the truck, but dealing with the hose is a pain.
If you fill the bottles, use a pair of forceps and pull the vent valve while it’s filling. Put the 20 pounder upside down after you’ve connected the 1 pounder. Tighten the 1 pounder so while upside down the valve is at the 2 or 10 o’clock. Pull the valve and open the 20 pounder to start filling. Once you have a steady stream of liquid propane coming out the valve, your done.
Don’t store the bottles in somewhere warm if they’ve been filled in the cold. In fact, don’t store them inside to be completely safe. The risk is overfilling and when their warmed they will vent.
After connected to the heater, your good. Since if it was overfilled a bit, it would empty by the time it warmed enough, and likely wouldn’t warm up enough in a tent.