Looking good. I think you need to bulk up the width towards the top of the shins, similar to how legs are shaped - thin at the bottom, then a slow curve out, leveling, and then curving in again towards the very top.
Also, when you talk about symmetry for something like shin guards, you usually don't talk about left and right side symmetry of the piece itself, but rather that the left shin and right shin should be exact, only mirrored to each other, as a completely symmetrical shin guard would look weird on your leg, as it goes against the contours of your leg.
Something more like this. Of course, I just chose the right shin, but the left shin seems less curved and more similar in shape on either side of the mid strip, so perhaps that's a better template to work from as it seems closer to what you have sculpted.