FIRST thing you need is a boat, or at least a seat in one. Either a drift boat or a river boat will work both have their place.
Personally I am growing to prefer the characteristics of a drift boat for this style of fishing, stealthy and able to work tight to the banks in the bigger water, 13,000 cfs and up. I love the range you get from the outboard powered river boats, but you do have to work the motor a lot more in the big flows to control the drift.
On the moderate flows 6 to 12,000 cfs where you can shut down the motor and drift on a drag chain, the river boats offer the ability to hit a lot more sections of prime territory than the drift boat. Tools for the jobs, and while I have preferences if you only have access to one boat either style works.
Fly size determines the rod you will be using. Normally a fast 6wt-8wt is standard. An 8wt sounds a lot but if you are determined to fish the really BIG flies then you will need the extra grunt. Grab the fastest sinking line you can find in your rod range. I personally like the Rio Outbound Short series, Type 6 for its ability to reach out with big flies, but SA’s Streamer Express 200gr is mounted on my 6wt. We have also sold a bunch of the RIO Outbound Custom lines with the customizable Tungsten head.
If you look back I used to suggest avoiding sink tips and going for full sink lines. But the modern LONG sink tips, 24′ and longer, particularly those with intermediate running lines really do work well, in fact its what I’m throwing most of the time.These lines really do slow down the faster rods, so lengthen your stroke and don’t try and throw arrowed loops.
For fly choice I’ll give you a rough idea of what is in my box when its fully loaded across 3 categories small, medium and large. Generally the small flies are the inch long stuff, Medium 3-4 and Large anything bigger. In some cases its not always about length. Ill put some light lightweights in the small category too becuase they are relatively easy to cast on your 6wts.
SMALL: Imitations of small sculpins and minnows and the like.
Whitlock’s Near Nuff Sculpins: Picking 1 take the size 4 Tan, Its a killer
Zonkers: White/Pearl has probably claimed more big fish than any other fly here
Rainy’s Carp Sculpin: Great profile and the brown version works
Buggers: Buggers do work well as a streamer in the larger sizes.
Barr’s Tungsten Slumpbusters: Neat little Barr pattern works very well and sinks fast
MEDIUM: Bigger sculpins & minnows
LARGE: big minnows and stocker trout.
You also want to have a BIG net, and a good set of pliers for bending down those barbs and some substantial tippet.
We have mostly settled on 15 lb test for our streamer with 3′-4′ of leader. Much longer and the fly won’t be pulled down fast enough in the current.