I like this picture - I think it will be helpful for you to keep in mind that every shot doesn't need to be as close as possible, plus it gives you a little flexibility with your final image as you mentioned above.

I prefer the horizontal crop, I think it gives the spider a sense of movement with him parallel to that blade of grass. You can sort of imagine him shimmying up his web to catch the gnat, and so the image becomes more than just a picture of a cool spider. And I don't consider cropping to be editing at all, it is just another option you have for framing your photographs, except you can utilize it after you've already taken the shot. Great job, babe!