I just renovated a bathroom and installed tile flooring. I bought bull-nosed tile to use as a base board. Can I install these base board tiles over the existing painted drywall and how do I attach them? This is not in the shower area and will not receive any direct moisture. Also, do I install them so that I leave a space for grout between each piece and what about between the base board tile and the floor tiles? Do I leave a space for grouting between the base board tile and the floor tile for grout?

Your install your bull nose with thinset or tile adhesive since this is so small of an area. You you leave a gap for the grout, size is up to you but use unsanded grout for a thin line and sanded for larger lines.