The best buy is the 20# tank. Disposable bottles just scream I really don't care. All the smaller choices 10#, 5# are expensive choices. In the design process if the 5#, 10# makes the design work definitely do it. But if the design process says a 20# works,,,,, just do it. Best buy for sure..
ps, if yer usage is miniscuke..... the using 3, 1# tanks a year is purely practicle. When one thinks of all the O2 bottles discarded on Everst every year....... one wonders about how many 1# propane bottles are thrown out every year...... and are they ever really recycled???
might be over the heads of a few, but can you justify the waste??