I checked online to buy some mono leader and i saw these two brands Offshore angler and momoi's high catch. The offshore anglers 500lb test leader has a diameter of 2mm and the momoi's 400lb test has a diameter of 2.06mm i would think for main line a smaller diameter is better so you can get more line capacity on your reel but as for leaders wouldn't a thicker diameter line be better for abrasion resistance? Or are the diameter differences so small it wouldn't even matter much if not at all? What do you guys think about this?
Use LP. Sharkoutlet has it.
A buddy of mine uses "longline" line but he kinda has a few miles of it laying around 
. Sharkoutlet is a good spot. I think they even have pre-made mono shark leaders.
Reguarding Heavy Mono To Your Shark Reel, I Would Guess That If You Have A 14/0 & Up Your Spool Could Handle Heaver Line Tied To Your Main Line, But The Knot That Connects The Two Would Be The Weakest Point Due To The Difference Between The Lines Diameters, Its Always Better To Have Fresh Line All The Way Through, But It Is Expensive To Full A 14/0 & 16/0 With Brand New Line, I Would Rather Go With Paying The Money For Ande I.G.F.A. Tourment Grade Mono & Tie 20ft Of Double Line To Your Leader. 
I did not understand what you were explaining if I connect the leader it would be connected by a swivel
Make A Bimi Twist & Cut The Bottom Tags And Tie It To The Swivel 
JP, He's referring to using heavy mono as his leader. (good points though)
I would think the thicker of the two (same breaking strength) lines would be a better bet for a leader, BUT keep in mind some brands are more or less abrasion resistant, harder and softer than others. Materials, manufacturing processes, quality control, cost, etc. All are factors. I used Weedwhacker cable once as a leader in a pinch, it worked fine on a few small/med tippers but when it was bitten off after a half second fight I never used it again . If I ever used mono for leader material It would have to be 1000lb longline. Dont get me wrong some guys use only heavy mono 500lb with circle hooks but Im sure they still get bitten off from time to time. As for me I'll stick to #15 and #19 singlestrand wire. But, "to each their own."
Yea Sandrayusmc, I Am Seeing More East Coast Anglers Using The Lone Line Shock Leader, Only Problem Is That We Have To Go To Your Neck Of The Woods To Get Them, But Its Worth It. For Some Strange Reason Tackle Shops Down In Miami Dont Carry Them, Thats Why We Learn To Double Line
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