Use the same formula for a tap drill that you'd use for a regular drill.
The best, the ABSOLUTE BEST formula is the one you derive yourself so you understand the principles involved and never, EVER have to come asking for that formula again. It's just not something any self-respecting machinist does in public. Not even a newbie.
Find the recommended surface feet per minute (SFM) for the material of the drill relative to the material you're cutting. (which you'd have to do regardless of whether you're drilling, milling, turning..etc).
Next, take the outside diameter of the drill and calculate the circumference, then figure out how many times that length goes into a foot, and how many times that has to happen in a minute, which gives your RPM.
The feed rate is an entirely different calculation, for which there is NO easy answer.
Without looking ANYTHING up or having any clue as to what kind of drill or what kind of material..... Use 300rpm and .003" feed per revolution.