why not using auto limit??
something like this E.G

on *:join:#:timerlimit 1 5 mode # +l $calc($nick(#,0) +2)
on *:part:#:{
  inc -u2 %fld
  if %fld >= 7 {
    mode # +i
    timeri 1 4 mode # -i
  }
  timerlimit 1 5 mode # +l $calc($nick(#,0) +2)
}

in this case if two users join the channel the third can not join that after 5 sec and if more than 7 leave this will execute mode +i bcz of limit isnt +2 yet

this is just an EG so i dont have mIRC here (not tested)
but u can have an idea