Questions again.

Mainly because leader material is different than main line.   While both are strong and will withstand the lb test listed, leader is stronger over shorter lengths and are not designed to be a long, main line product. The main lines are designed to take the impact load over a much longer distance, transferred throughout the line and pole.   Generally  leader is thinner  and stiffer compared to the same lb flouro (not always).     It helps with line shy fish.   I think knot strength is better with leader material too.
 
 You can also step  down in line lb  size with your leader so as not to spook them.  Also some guys taper leaders like in fly fishing as the taper distributes the line stress and lets you fish with smaller lb on the end for line shy fish. 
 
You can use the flouro as it probably won't matter that  much with the sharks it eliminates the swivel and   really there is no need for the break in the line except in the DSR where it is a rule.  Back a few years ago you needed a swivel to be legal.  
For Steel I would spend the money on leader material though.

I broke my fly line so i had to spool with mono. went with 12lb. cortand camo. In the fast water of the am i didn't use a leader and was very successful. As the day went on i tied on a swivel and went to 10 than 8 pound fluoro leader. I agree to with the fact that if you have to break one off you dont lose your main line in the river, just to the swivel .
 
CP

fluoro's have some QC issues too
many of them are brittle
also its not a great idea to use them on a spinning reel, if they loop then kink they loose alot of their strength

Thank you all again for the quick responses. I have the 12# XT line on my spool right now. I also have swivels and 8# flouro leader in the box. Being that i will most likely be going for kings next week should i put the leader on or is it not worth it? Im taking it from the responses, that the kings right now are a different type of fishing compared to the hos and steel.
I did make a reservation and am going up mon through wed or thurs, depends on the fishing.

I would start with 8# leader..  If you get lots of break off or fishing around a crowd then make the change.. Basically let the fishing dictate..
On that note, if catching, landing fish with 8 is no problem then UP to the 12# still using the swivel > leader.. (edit)  Charlie is right, 10 would be an all around if you go to  fluro..
My fly rig was 12# tippet at all times 9 days ago.. It was obvious the fish were line shy .. I was trying for aggressors so it didn't deter me to see fish move away.. I didn't use a swivel on my fly rig, you should on any spinning rig.. I will soon..
If I were fishing now, I'd be dropped down to 8.5#  (3x) frog hair mono tippet.. Will hold kings and fool trout..
 
In winter I will use (3x or 4x ) frog hair fluro as that brand reacts different in temps, fluro is way better cold then their mono.. Screw Seguar, all bad experiences from my end on that stuff..
About 2 #7 sinkers (1/8th oz) should be all you would need anywhere on the river in these conditions.. Most times less.. An assortment of 7,3/0 & bb will suite all needs.. 
 
As for the lodge and fishing, Please report back..
I stayed there when it first opened and Tom owned it.. Not since, still looks the same and my experience then was good .. Same was said by Pa.. The owner was very friendly and welcomed us strangers..
 
Good luck..