Ive been spearfishing and grabbing lobsters since 1987. My favorite so far is a 48" biller. The wood ones will float out of your way while you are stringing your fish. I would use 2 wraps of 400lb mono for your line. You may have to resort to some custom shaft bushings to attach the line. Billers don't work well if you are using riffe bands on the gun as I do. The only failure Iv'e had is once, I shot a snapper about 36lb and didnt roll him. He turned and shook and broke the shaft above the point. Point choice is important as well. I used to use a tri cut point, but I switched to a pencil point... they dont cut, they they skewerthe fish and there is less chance of a tear out on a grouper or A.J. Good Luck.