There shouldn't be any problem with breaking it down and storing it in smaller bags as long as the method is the same. Then you can store all your smaller bags in the bucket for convenience. I've distributed mylar bags of oats and other items to my parents for their storage.
Also, if you keep 02 on hand you can always break open a 5 gallon bucket, pull out what you need, drop more absorbers inside and reseal the mylar.
I haven't actually tried this but you shouldn't need need electricity to reseal a mylar bag, just heat. I have one of those old fashioned cast iron Irons. You can find them in antique shops or sometimes at thrift/second hand stores. My grandmother used to use them as bed warmers and when not in the bed they were used as door stops. Put in/over a fire to heat and use to reseal mylar that way. Matter of fact, I also have an antique cast iron Bacon Press. That would probably work also if you have one of those. Gonna have to try it for myself and see if it works. I have some Vac-Sealing and Mylaring to do here shortly. I'll post back.