I also use a Kowa with 25x magnification (Kowa 661 with 25x LER eyepiece).
My Bushnell Spacemaster is a 20-45x60 with a LER eyepiece. I rarely use the upper range of the variable magnification. I usually keep it dialed down to 20x because it's clearer and easier to see if mirage becomes an issue (and it usually does in California heat).
For the most part, a 12-50x50 should suffice at 100 yards.
Remember: The key to spotting scopes isn't the magnification, it's the quality of the glass.