Unlike the cube metering valve, the K-valve is NOT meant to be used with a blank pill in it for naturally aspirated applications. A supercharged deal has a ton more fuel going through it at idle and that extra hole "jumps the pill" at idle and gets rid of excess idle fuel. It blasts through that hole you're missing, and straight across in front of the pill and out the idle check valve along with what shoots through the pill. As soon as you open the throttle, that circuit is closed and the main pill is it. That circuit isn't used in naturally aspirated...the pumps for those setups are much smaller and the idle check valve is generally set at only a couple of PSI for those. Not a ton of flow to deal with. I think if you drilled that hole, your idle setup would change quite a bit from it.
Drilling a hole to bypass to the pump saver at wide open throttle is a little scary unless you are only using it strictly for an electronic high-speed sort of port. A simple tee anywhere in the system would also do that and add the benefit of helping to bleed off fuel when the throttle closes at high RPM just like a pump saver (if you're using a regular spring loaded check valve). If you supply it through a WOT hole like you mentioned, then it can't help you that way.
We carry spools with no slot and no holes at all for people that like to do their own thing. I've not seen a notched version with no holes, but they probably have them. Give Enderle a call and see what they have or buy a blank from us and see what you can do!
Spud