Ideal drill bits for DBS-22

[wallbc]

For general drilling of wood, regular steel and aluminum what type of drill bit would be best for sharpening with the DBS-22?  I am assuming that with any of the cobalt and titanium coated bits the coating would be removed on the initial shaping of the four facets?  I don't really want to spend $1000+ for a set of solid carbide bits and I fear they would be very difficult to sharpen. So is a set of plain HSS twist bits my best option?  Also can you buy bits off the shelf that are already four faceted?