Now that I got VPN working on my 3500L's

I got a router to router VPN working with my two Netgear 3500L's   It works great and I can ping everything from both networks.

Now I have a question about the actual capability of the 3500L's as far as how many connections and/or VPN tunnels they can reasonably handle.  How many VPN client routers can I cannect to one 3500L running Tomato VPN server?

Of course the netgear site does not say anything about this since the native 3500L setup does not support VPN.

Thanks,

Tom Travis