Then you misunderstand if this is based on something I posted. I said that you cannot you servers from multiple companies. They must be servers from either Company A or Company B - you cannot mix them.
Then you should be able to use the instructions I posted above. The URL leads here: Force Google SafeSearch on Lede 17.01.4 - #8 by lleachii. If you do not get the desired effect, you have not configured something properly.