What are you using to cut them? If a pipe cutter, the tubes will interfere with each other. If a hacksaw(or anything else), securing the tube being cut can be an issue.
A complete breakdown may actually be the path of least resistance.
P.S. If you cut them with the base casting still attached, you have no good reference to the ends to determine where "12" inches is. Also you will end up with 4 flapping tubes.
Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E(SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange