ques on Wifi N/W..

Typically 253 as limited by the netmask. Some cheap access points blow up at as few as 5 wireless connections. The better ones claim

I've tested some about 6 years ago with about 100 live wireless

Sorta. One can be a wireless router, but the other should be configured as an access point (same as a wireless router but with the ethernet router section disabled).

Note that you don't actually need to disable the router section, you simply don't plug anything into the WAN port.

Also be careful to disable the DHCP server in all but one device on your network. The link jeff posted probably said that mind you.