K&S thin brass strip works fine, just cut it into one inch pieces, put the cells next to each other, solder and bend. Use a little flux on the strips to get a good colder connection. No need for a shotgun tube or end caps, just shrink wrap the whole dealio and you're good.
Trinity stuff is OK but the strips are thin and kinda flimsy & really require that you use the shotgun tube which can get in the way of the Mini innards if that's the direction you're heading.
I've never lost.
I've just been a little bit behind when time ran out...
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