KWP, I’m going to toss my .02 cents worth in here for what it’s worth.
When we accidentally catch 6 to 10 pound walleye’s we used the 50 pound hook style Rapala scale.
There is a benefit to going to the 50 pound scale for the guy that accidentally catches something that he wasn’t fishing for. (It’s a standing joke that when a walleye guy catches a catfish with out a large enough scale, it automatically becomes a 50 pounder )
As far as the hook or clamps style goes, it’ really doesn’t matter. I groan when I see any fish held up with a Berkley scale or the Rapala model.
I prefer placing the fish in a net then subtracting out the net weight. Some will say the net takes off the slime coat, but most people net the larger fish they will want to weigh anyway. Bring the fish in the boat, have your scale handy, take a quick weight and any slime removal will be minimal.
For on the ice (without a net) I like to use the Team Catfish Floating Fish Grips. They have a wider contact point then the scales and have a hole in the handle of the grip to connect a scale. Plus using the grips, your hand won’t get wet.
/.02