I just purchased a 42" speargun as my first gun. It was used, and needed bands and a shaft. After searching around a bit, i found that 9/16 X 20" bands would be best so i got those. It is a rear handle gun, so i was told that there should be like a 6" hang off on the spear...i wanted some help on what size shaft to buy? I was thinking a 48" shaft since it is a 42" gun, and a 1/4in diameter with a flopper....any input would greatly help!!!thx