In order to take advantage of this rolling pin, I made some modifications to increase the rate of success. I hope these recommendations will help you improve yours
1. Remove one of the rubber gaskets at either ends.
2. Lubricate the log. Use a less viscous lubricant such as silicon lubricant or the oil you usually use for hinges and bikes. Since you want to account for the lightest possible weight of a mouse, it is best to minimize the resistance of the log. Petroleum jelly or other gel-like viscous grease, as what the manufacturer recommends, imparts some amount of resistance to the log from rolling. You could either remove the log from the pin or just spray the inside and roll the log to spread the lubricant.
3. cut out 2 round boards from a carton approximately between 2-1/2" to 3" in diameter and cut out a hole in the middle just enough so that the boards are robustly snug such that it provides grip onto the log when being rolled.
4. Position the round boards in the middle of the log, leaving a clearance about a quarter of an inch between them. Put a small amount of peanut butter between the boards. Small amount means the peanut butter does not touch the boards, does not drip, and does not cause imbalance on the log.
5. Replace the rubber gasket and insert the pin in the hole. Check if the log is rolling smoothly and that the peanut butter bait does not fly away.
6. Some people would put peanut butter along the way to lead the mouse to the main bait. This is a stupid idea. Mice have very sensitive sense of smell and they can detect the exact location of the bait. As I've said in #4, just put a small amount of peanut butter between the stopper boards, and the mice will find it. If you put peanut butter along the way, the mouse would be full by the time it is about to reach the bait and would hesitate to walk on the log sensing that it is unstable. Hunger and the overwhelming whiff of peanut butter will deprive the mouse of any reason to be logical or apprehension.
7. The 2 stopper boards will be to prevent the mice from getting into the bait on either side and they will be forced to climb up the board to get to the bait. The outermost part of the boards will cause the greatest moment to the log, which will cause the log to rotate even with the slightest force as if there were no resistance. The mouse would attempt to kick the board which will cause it to rotate faster, causing the mouse to lose ground and fall into the bucket.
I suggest to the manufacturer that to increase catching rate, they include a part like a wheel about 2-1/2 to 3 inches in diameter, preferably made of plastic, to increase slippery, which could be sleeved in the middle of the log snugly and where peanut butter bait can be placed. The distance between the wheels should be small such that the mouse would be unable to get its head in. Please refer to the picture I attached and the improvised bait wheel.