There is no reason to keep Glyphosate in heated storage.  It's a salt, it won't freeze at any reasonable temperature.   I have about 70 gallons or so left in a cage tank in the shed right now.  

250 gallon Cage tanks are virtually free with chemical purchases.   I was looking for them a couple years ago, now I have enough to load a semi trailer and don't really know what to do with them.   

Water supply doesn't look like that big of a problem to establish to me.  A 2500 gallon tank ($650) with a float valve ($30) on a garden hose ($20?)  with a Chinese transfer pump ($160) and a couple hoses and you are set up.    

I've had "warranty backing" on about 40 acres in the last however long I can remember spraying several acres per year.   I'll take the low price and worry about that if it happens.  I know how it works but there really shouldn't  be any difference in warranty dependant on what retailer you purchase the product from.