Share 'extending aluminium tube with wood for Tiki mast'

hi, folks I have a little question here. After sniffing around I finally managed to find long enough 100mm alu tube for my Tiki, but still not long enough -- 6m is the longest one one may acquire in our NE corner of Europe... So now I have a two options, shall I extend it with hollow hardwood or laminated soft wood... ... with one 1m piece on the foot section, 0,6m stays out and 0,4m inside the…