I didn’t have any paternity tests but I looked at my kids feet for sure. My feet have predominantly longer middle toes than the big toe. My wife’ toes are descending in size from the big toe. The second thing I checked later on was there hereditary ability to roll their tongue like me. The wife cannot, but they can, like me.
Literally neither of those traits would be indicative of paternity.
As with any dominant trait, unless you have some way of knowing you are a homozygous carrier, you could not be sure that you would always pass the trait to your offspring so lack of trait would mean nothing.