If You are only using 5/32 & smaller rods You should be fine with the #3 whip of 25-30'. You can get away with a shorter length of smaller cable, but if it gets too long you will have too much voltage drop from resistance. The tables show #3 being OK for 150 amps up to 100'. That 100' includes BOTH cables, stinger and ground. You get some resistance at each cable end connection, and some in the twist lock joint, it ain't a perfect world. Keep the setscrews tight.