Made and tested on mIRC v6.35

Place in a new remote file.
This is a mirc popup menu script and is activated when you right/click your mouse button in a channel
window to pull up your options.
Find [Auto Voicer] in the list and hover the mouse pointer over it. Select Channels/Add to add the channel you wish to
use this script in.

The Users/Add blocks the nick from being auto voiced on join.
Setting a channel to +M would make this script better as enforcing voiced nicks on joins.
And also allow nicks that are not voiced to remain muted.
Note: That fellow ops will not remain muted if they use /ns update and are still on a channels
access list as a channel op.

I also made viewing windows so that the script user may check the current status of whats listed.

Oh Ya... no lame comments like:
why not set a channels auto voice with
/msg ChanServ LEVELS Channel here SET AUTOVOICE -1

I'm not a noob to IRC servers

on *:JOIN:#:{
  if ($me isop $chan) {
    if ($ini(voicelist,chans($chan,2),0) >= 1) || ($readini(voicelist,chans,$chan)) { halt }
    if ($ini(voicelist,$address($nick,2),0) >= 1) || ($readini(voicelist,nicks,$address)) { halt }
    mode # +v $nick
  }
}

menu * {
  [Auto Voicer]
  .Users
  ..Add User:/writeini voicelist $address($1,2) $address($1,2) $1 | writeini voicelist nicks $1 $address($1,2) | echo -a 4 $1 $address($1,2) was added to Voice List.
  ..Del User:/remini voicelist $address($1,2) $address($1,2) $1 | remini voicelist nicks $1 | echo -a 4 $1 $address($1,2) was removed from Voice List.
  ..Read User List:/window @DevoiceList Verdana 13 | echo @DevoiceList The following names will not receive +v on entry. | echo @DevoiceList [Nicks] | var %nicks 1 | while (%nicks <= $ini(voicelist,nicks,0)) { echo @DevoiceList $ini(voicelist,nicks,%nicks) on the ip $readini(voicelist,nicks,$ini(voicelist,nicks,%nicks)) | inc %nicks 1 }
  [Channels]
  ..Add Chan:/writeini voicelist chans $chan $chan | echo -a 4 $chan was added to Voice Channels List. 
  ..Del Chan:/remini voicelist chans $chan $chan | echo -a 4 $chan was removed from Voice Channels List.
  ..Read Chan List:/window @ChannelsList Verdana 13 | echo @ChannelsList The following channels will not voice nicks on joins. | echo @ChannelsList [Chans] | var %chans 1 | while (%chans <= $ini(voicelist,chans,0)) { echo @ChannelsList $readini(voicelist,chans,$ini(voicelist,chans,%chans)) | inc %chans 1 } 
}