I don't own 55's. I think the 55 was made with the Mink trapper in mind. As you said, they are smaller, but 'fit' in Mink trails and smaller opening because they are compact. They are used for 'small', 'tight' spots.
I now use 110's for bottom edge sets on stream beds. Rarely I use them on land, because I use footholds for Mink nowadays.
I don't use boxes for Mink.
Years back, I set 110's on land, and used a few Mink boxes. I've set enough of these and enough years to give you some feedback on my experiences and observations. Although my style changed over the years.
I was using 110's years back and was having trouble catching Mink in them. I wasn't having trouble catching 'em with footholds at the same time.
I told a friend, Russ, of my troubles with Mink not going thru my 110's. He said he was videoing some sets and noticed how the 'black, dyed', 110's stood out in tan weeds or tan cattails or snow. This was back when video cameras were as big as a Beagle and balanced on your shoulder only shooting BLACK AND WHITE picture (remember?)
This seem to be a revelation to Russ because the 110's stood out from surrounding weeds.
He started painting his 110's Tan color and put a few small brown marks on the Tan to create a camo'd 110. By painting his traps Tan, he began to take Mink on a consistence basis on land. I think at this time frame Russ began to use thin wire strung between the trigger wires to increase catch, as you mentioned.
So I painted a few 110's and did the trigger wire and caught Mink. But my Mink style changed by then.
Am sure the 55's will work for you because they were designed for Mink.
I would consider painting your Conibears Tan with brownish spots to break up outline if used for Mink.
Learn as much about Mink as you can. They do have trails and habits which may take some time to learn.
