Attempting to recreate Mom's coleslaw dressing

My mother made the best coleslaw dressing in the world. I grew up on her dressing and none I have ever tasted comes close to being as good as her's. 

My mom always cut her cabbage herself and grated the carrots. I buy the prepared bag but since the dressing is the important part, I am not feeling guilty about the shortcut. 

I looked at a bunch of recipes online to get one that seemed to be similar. I knew she used mayonnaise and vinegar. Sugar was also added. Horseradish is what gave hers the zing. 

After trial and error I came up with this dressing which is close, but still can't compare to the one of my memory. 

1 cup mayonnaise
1/4 cup white vinegar
1 tablespoon plus 1 teaspoon of white sugar
1/2 teaspoon salt
1/4 teaspoon of pepper
1 1/4 teaspoons of horseradish

Add all the ingredients to a small bowl and whisk. Taste. Adjust for your own tastes. Put in a glass jar and shake. You can now store this for a day or two use it right away. 

I sprinkled sugar on the salad and added a little extra horseradish when I actually put it all together and it was really pretty good!!