Don't worry about using the larger sized batteries. Here is the guideline I use for sizes larger than 18350.
1. Remove the battery cap.
2. Remove the battery.
3. Insert the new battery.
4. Adjust the battery tube so that 1/8" of the battery is sticking out past the threaded end of the tube.
5. Screw on the battery cap.
Thanks Yzer!


That is a great rule of thumb to use!