I am planning to install two 36" solid wood floating shelves in my half bath. Each shelf weighs about 11 lbs. My question is: can I mount these shelves on the studs in the half bath? - see red circled studs in the photo - the photo was taken during framing, but the bath is now fully finished with dry wall.

I am concerned that the screws might split the studs during installation or that the screws may not be properly centered and therefore go into the edge and not hold properly, because they would be going into the narrow sides of the studs rather than the wide sides. Note that the horizontal wide wooden studs in the photo cannot be used for mounting as they are not at the right height for the shelves.

The manufacturer of the floating shelves could not advise me on whether or not I could install into the narrow edge of the studs, though they did recommend using toggle bolts if I could not. I am a bit concerned about the strength of the shelving if I were to use toggle bolts though.

Thank you in advance!