I don’t have any 159 size but I have caught mink in dry 220s. As far as lethality of 110s give them plenty of wire to get out in the water. Many sets are just in the edge above the waterline or up a bit on the bank. They don’t navigate well with a 110 out in the water. I actually find the 110 and 55 sizes fine for any mink trapping I want to do. I guess if you have a couple hundred 110s you use what you got,

i'm probably 65 percent 110,25 percent 150,10 percent 160.way different area here than Aix.a bigger thing i've found lately is spring strength.2 yrs ago i sold every conibear i owned and bought all new after playing with a couple new ones and realized how weak and SLOW my old ones were.all the parts being there no longer made it a viable mink trap in my mind after that.amazed how sore my hands got last winter from setting new traps all day.

Im the opposite, I prefer a bit weaker trap and buy used when I can. Ive seen some new ones that were so strong the trigger wires would start to bend a bit before going off. I was afraid that would cost me some mink. Ive had some live ones in 160s on the bank but I think it was due more to where the strike was than the strength.

for mink I was taught 120's on dry sets and 110's if they can/should flop into water.
I like 160's or 210's for rats