I purchased the 8 inch concentric for my Vaquero. Took it to a small yard to find the marker pins.. Yard size about ten feet by twenty five. I found a Roosevelt dime, 1962, and a plated silver heart.. Ground balancing seems to be more subtle when compared to the stock 9 by 8.. Kind of hard to explain since I've had the coil three days, and less than an hour fooling around...Over the next several days I will be comparing the 8 incher to the stock coil. A trip back to my crazy yard, and possibly another trash laden yard before I hit the 4 1830's sites I have. One of the reasons I wanted this coil is a water site I would like to check. The concentric coil should slide through the water with much less resistance than the stock Spider type coil.. It has been a while since I've gotten out, and even forgetting my knee pads, it was great to go swinging...If you have any advice, or comments, about using the 8 inch coil, am all ears. And, thanks to Tabman, for the comments, and Bewhole for holding. Am up to three silver coins so far this year.