There is a field in MecaStack where the user can specify the spacing of anchor bolts. The reason for this field is that there was an excerpt out of the publication "Wind Loads and Anchor Bolt Design for Petrochemical Facilities" by ASCE published in 1997. The anchor bolt information was actually removed in later versions of the publication, we aren't sure why. Here is what the guide indicated about anchor bolt spacing.
In our design work at Meca, we have sometimes seen similar spec's. The values we have seen have ranged from 6 to 8. In all honesty, for years we never considered any minimum spacing, and as far as we know it has never been an issue. In the effort to be thorough, we added the parameter to the baseplate section of MecaStack and the user can enter whatever value they deem neessary.