The quickest and most reliable way to find all the numerics you need is to first turn on debug with /debug -p @debug, and then do a /whois on yourself with IRCop priveliges when you have an SWHOIS set. You can set an SWHOIS for yourself in your operblock; there may also be a way to temporarily set one using the OperServ RAW command (don\'t mess with that if you don\'t know what you\'re doing though, of course).
Also on large channels, it is likely to RecvQ you off. While a SendQ could be prevented by combining it into a /whois nick1,nick2,..,nickN command, this won\'t do anything for your RecvQ, since the server still has to send you the same amount of information. In order to prevent a RecvQ flood on larger channels, you should use timers... PM me if you want specific info on how.