Sharpening your waki will be fairly easy with the right stone and technique. Ceramic are not something I recommend for carbon steels and are very fine so if used it would be in the final finishing steps.
Oil stones, water stones, and sandpaper are all excellent options for this steel. Because of the more abusive nature of what you will be doing with the waki a high polished razor sharp edge is really not ideal. Its not a light cutting tool so edge damage will typically be higher and occur more often.
For sharpening and up-keep I would recommend a Norton combo india stone in at least the 8in size or better yet the 11in. Coarse to repair and fine to get a sharp usable edge so you can get back to having fun.
The technique used will be similar to those used in Japanese sword polishing. (check youtube for reference of hand position and stroke technique) I'll try and get a link up in the morning.
Though a oil stone using water or soapy water would be best. Start by placing the waki on the coarse side of the stone, starting at the choil. Place one hand on the handle and one hand on the forward section of the blade. Make short strokes like sharpening a smaller blade but overlap your work and evenly progress too the tip. As you work to the tip take caution as your hands will both eventually be on the blade.
Really not that difficult just intimidating because of its size.