Hiya
Ron S, i use a single fairly soft 20mm band, as yellowtail's flesh is easily penetrated. I also have an open muzzle on my 115cm Rabi Apex, but prefer the closed muzzle design for yellowtail hunting. I find i can load the closed muzzle much quicker, as i don't have to bother with putting the line on the line release. Speed of loadind is VERY important, as often you get only one school of fish and you can then spear 2-3 fish very quickly, before they leave. Also helps when a poorly placed shot tears out and the school is still around!!
how do you like the single flopper shaft for YT
I PREFER the single flopper!! Quite simple, slip tips are a NIGHTMARE to remove from fish and often you'll find that you can spear a yellowtail, load the gun, whilst the fish is still swimming on the spearline and spear another one, whilst the school swims with its captured friend!! Not possible to do this with a slip-tip. Once again, here, speed is the name of the game. The faster you can do things, the more fish you'll end up with.
How-ever, if you're planning on chasing TROPHY class yellowtail, i'd go for a slip tip. MUCH better holding power, which helps on poorly placed shots on bigger class fish.
Also, do you use a single or double wrap of line?
Single wrap. Most of my spearing is done around structure, be it reefs, wrecks of kelp. Give a yellowtail a bit too much line and he'll wrap you up around the nearest obstacle. Since i shoot a single 20mm band, the penetrating range of my 115cm Apex is pretty much at the maximum when it reaches the end of my spearline with a single wrap. Also, much quicker to reload with single wrap.
How-ever, once again, if you're targetting only trophy sized fish, in rather open blue water type conditions, with very little obstructions, then a double wrap will give you THAT little bit of extra range, especially if you're using 2x16mm's and even more so when shooting downwards.
What i've found works well on larger class yellowtail, 10-20kg+ (20-50lb+) class fish, is to shoot them at a 45degree angle from above. I find that i lose less fish when shot like that and also get less bent spears!!