How to set drag properly with a digital scale?

[MuskieBait]

I would set it on the quick pull.

When a fish gives a quick run, there is no time to reset the drag. On a quick pull, there is so much force applied to the spool to work against inertia (from a 0 movement moment to getting it to move) that force builds up very quickly. Also, there is more friction due to the quick pull vs. a slow slip. The way you can experience it yourself...take your elbow and drag it as fast as you can across the table top...you'll feel that friction burn very evidently...now, take the same elbow and run it steadily with the same force over the table top for the same distance...and your elbow may experience a little warmth but not a burn. Friction burn...you know.

When you pull line that quickly, the friction increases temperature of your drag. The heat cause the metal washers to expand...and expansion of the washers increases drag pressure. In extreme case, the heat also start to turn your grease or oil less viscous and it could thin out your lubricant so much it starts to squeeze out of the drag material. This may then reduce the lubrication of your drag in thus further increase friction between the materials. Drag pressure will change as your drag stack heats up.

That's the gumming and sticking that you hear about with a hot drag.

When the fish is holding its ground, that's when you need the slow slip. If it slips at a lower drag pressure, you can always palm the spool to add a bit more pressure to hold a fish.

One other factor to consider is...do you have a full spool of line or half a spool of line? The circumference matters...a full spool of line pulls out more inches of line per rotation, but the drag pressure is spread out over more inches of line. With half a spool of line, less line is paid out over the same drag setting...thus there is more drag pressure per inch of line per rotation. That's why on a long run, it is advised to readjust the drag to lower the drag pressure as the line comes off the spool and the circumference decrease.

As much as some people say not to adjust the drag when a fish runs, or while fighting the fish, that doesn't always apply...especially with fish that runs off a huge amount of line in a hurry. For a lot of the local freshwater fish, you likely don't need to readjust drag during a fight since these fish usually don't even strip off 100 feet of line at all...so the drag pressure change is not even a worry.

BTW, that 1/3 rule is just a guideline. The exact drag setting you use could all depend on the species you are after (are they known for long fast runs or short bulldog fight?), your rod action (slow vs. medium vs. fast) and how much lift you put into the rod during the fight. As you lift your rod, the pressure on your line increases. It depends on how you fight your fish sometimes.

What I would do, if I were you, is to measure out drag setting in terms of lb of drag, and then hand pull at a medium, constant speed to FEEL what 15lb of drag feels like for example. Familiar yourself with a bunch of drag settings and then you can adjust on the water to the species you are after and the different rods you may use. There is no single hard rule...and that's where experience often comes into play. Plus, as the fish near that stage where you land it, you often have to lower your drag setting anyways due to the short amount of line between the rod tip and the fish, plus a usually fully bent rod. Fishing heavier drag is where you may pull a hook, snap the line or snap the rod during that critical stage of the fight. Once you decrease your drag, you have to readjust it on the water anyways...so it is helpful to know BY FEEL what approximately lb of drag you are setting. I think knowing the upper limit (eg. 10lb as max limit for 30lb line) is important so you know NEVER to exceed that particular amount of drag by feel.

To be honest, I haven't measured out drag pressure thus far. I always set it a bit lower to err on the side of safety, and then increase it later as I see fit.

I'm always surprised, after landing a big fish, how light my drag actually feels for the size of fish that was landed. That's due to adjustment of the drag during the fight to protect the line from breakage...and often you don't need that heavy a drag at all.