finally got this stupid achievement and it wasnt from one of the different settlements i built using different "methods" for a guaranteed 100%, had 2 settlements trying to use the 2 settlers, one for food and one on a 3rd tier clinic strategy, another 2 settlements at 20 people with most everybody on either a clinic or bar, i finally got it at finch farm where i wasnt using any specific build, just had some fun with it cuz you could build up on the highway there, ive also found out that with a bunch of built up settlements close or at the max build limit, my quicksave/regular saves take a lot longer to complete and my game crashes a bit more (im on xbox1) so now im going through (at level 87) with the sandman perk and killing off my settlements one by one and scrapping them in their entirety to be able to build to my hearts content at one or two of my favorite locations (murkwater, hangman's and starlight)