Re: which Kowa scope?
Objective size criteria:
1. Size/Weight,will you be carrying your scope long distance in a pack? If so, get the smaller one, if not get the bigger one
2. Cost, the larger one costs more
3. Magnification, the higher magnification you use, the larger the objective you want. I am very happy with a fixed 30X wide on my 65mm Swaro.
Zoom vs fixed:
-You usually get a wider field of view at the same mag with a fixed.
-I think the my fixed are a little clearer than the zoom it replaced (Swaro 30x vs 20-60). Think the fixed has fewer lenses.