I strongly suggest you keep the stratum proxy and blade on the same cabled connection. I started to attempt something like what you're going for and was immediately seeing performance hits(~93% to 96%). Measurable from both the blade's GUI and from the pool sites I'm on.

However at this time my blades -are- on wifi at the moment, but not with an extender, and constantly above 98% utilization.

I have my PC's ethernet port plugged into an umanaged switch with all the blades, static IPs for all of course(including PC) from there "Slush's Stratum Proxy" is automatically bridging the connections from my Ethernet port to a Wifi dongle, it was amazingly simple once I realized it could do this. Literally all you have to do is set blade IP's, a computer IP that you point them to, and run the proxy.

Also it's pretty easy to get it talking to other pools like Eligius, ask if you need any help there.