Originally Posted by kadesean
Those aux tanks that go where the side covers go are a bit of a plumbing headache. They only hold about 1 liter each. It's a lot of pain for 20 miles of range. There should be plenty of 6.1 gallon OEM tanks available. Check all the usual used airhead parts suppliers.
What he said,
plus the fact that the Luftmeister sets are bringing BIG bucks, Like HUNDREDS of dollars. Screw that, the 6 gallon is the way to go. Just be very careful of rust-out. The area behind the knee pads is famous for developing rust issues due to the trapped moisture between the tank and pad. I've seen many an original beauty leak there. Hard to know unless you peel back the pads.