I follow Bret Clark, if he falls through I take a different route. Hey that’s the advice I got from his Dad years ago.
Oh, the question was what kind of spud. I bought one at Ace Sportland in La Crosse that’s very light weight, the shaft is a 1/2″ rod with a 1″ blade at the bottom and T-handle on top. I like it because it’s light to carry but still gives a good wack into the ice to test depth. If you were going to use it to chisel holes then it probably wouldn’t be the best choice.
I have the T-Bar handle spud also. I painted marks every inch below the T-Handle for measuring ice thickness. I chip open a small hole, hook the T-Handle under the ice and read the thickness. Helps keep me honest when my eagerness to get out makes a true 2″ into a “looks like” 3″ Ingy