Hey WhiteThunder, 
Got a question regarding best practices just so I know I'm doing this the most efficient way. 

I'm using a custom outpost on my map. Because the "Outpost" map wording can sometimes be obscured by vending machines depending on the orientation i tend to move the Monument Marker around. If this is set to Custom Bounds, this of course moves those boundaries and they need to be adjusted each time. Though getting this perfect each time is near impossible. So anything from Monument Addons will likely be off slightly.
The alternative is to have Auto determine from prevent building volume, this leads to a big bounds box. But will remain the same (including position and rotation) each time I bring the Outpost prefab in. Are there any negative effects to having such a large-bounds box? Can i streamline this?

With Fishing Villages, the two smaller villages appear as "Fishing Village" whereas the large one appears as "Large Fishing Village". 
The smaller two default to B & C in the config. But if you're using custom fishing villages do they have to have unique map names?

Many Thanks

Great questions! There are multiple minor risks with having a large bounding box. Ultimately it depends on which plugins you are using that depend on Monument Finder.

1. Monument Addons will allow you to place objects in locations that are obviously outside of monuments, which can become an issue when the same monument is reintroduced on other maps, where the surroundings may be different. The plugin tries to partly account for this by allowing objects to auto snap to terrain, which is a property per addon that is automatically enabled if you originally place the addon at terrain level.
   
   Mitigation: Be careful where you place addons, and test on multiple map seeds.
   
   
2. When a smaller monument overlaps with a larger monument, Monument Addons may associate newly placed objects at the wrong monument. This is something that Monument Finder can improve on eventually, by using smarter logic to determine which monument is nearest, but I'm not aware of anyone running into this issue yet.
   
   Mitigation: Pay attention to the chat message when you first place the addon, which tells you which monument the addon was assigned to. You can also place the addon at one part of the intended monument, then use Telekinesis to move it to the part where the monuments overlap. For repeated monuments, you can find a different instance of that monument that is not overlapping, and create the addon there (which will be automatically applied to the monument that is overlapping).
   
   
3. When a smaller monument overlaps with a larger monument, if you have an existing addon, such as a vending machine, other plugins such as Custom Vending Setup may associate the vending machine with the wrong monument, which can cause it to fail to apply the customizations you made on new map seeds.
   
   Mitigation: Set the Monument Addons config option "StoreCustomVendingSetupSettingsInProfiles": true, which essentially ensures that Monument Addons stays in sync with Custom Vending Setup about which monument the vending machine is at.
   
   
4. If you use a plugin which announces to the player when they walk into a monument, if that plugin depends on Monument Finder, having larger bounds means players will see the announcement sooner.

Overall, these issues are pretty minor, and since you are editing the map, you have more options on how to mitigate them.

Regarding fishing villages, vanilla monuments are identified uniquely by their prefab name, not by their display name, so Monument Finder has no problem differentiating between the two smaller fishing village variants.

Thanks WhiteThunder, while my safe zone monuments are custom. I'm only likely to use Monument Addons in the outpost. So in theory I shouldn't really have anything crossing over. 

Maybe RustEdit will come up with a solution for keeping the markers in the prefab so their placement can be guaranteed each time.

Sorry, another question... from my experience most monument prefabs use Sphere Prevent Building volumes. What if I used a Cube Prevent Build volume? Can Monument Finder tell the difference and could that be used to determine the monument bounds instead? 
That way you could have the what i assume is standard size prevent build zone and a more tighter bounds zone.

Another option which you would have to test, is to make Monument Finder determine the Position and Rotation of the monument according to the Prevent Building volume, but use Custom Bounds. It's been a while since I worked on this plugin, but I vaguely recall thinking of this use case, which is why Position, Rotation and Bounds are all independently configurable.

Monument Finder supports both Cube and Sphere Prevent Building volumes. When you use a Cube, the bounds should match what you see in RustEdit. When you use a Sphere, the bounds will be a superset of the Sphere volume, as though there was a Cube containing the Sphere. Using a Cube is likely more advantageous as it allows you to get away with a smaller volume (with a Sphere, you have to enlarge the volume to cover the corners, which has the consequence of increasing the bounds).

It looks like this worked, i'll do some some testing on a few different maps at a more reasonable hour when i know i'm thinking at 100% but so far it looks good. This was the setup i went with based on your advice.

"Outpost": {
      "Position": {
        "Auto determine from monument marker": false,
        "Auto determine from prevent building volume": true
      },
      "Rotation": {
        "Auto determine from monument marker": false,
        "Auto determine from prevent building volume": true
      },
      "Bounds": {
        "Auto determine from monument marker": false,
        "Auto determine from prevent building volume": false,
        "Use custom bounds": true,
        "Custom bounds": {
          "Size": {
            "x": 200.0,
            "y": 50.0,
            "z": 200.0
          },
          "Center adjustment": {
            "x": 0.0,
            "y": 12.0,
            "z": 0.0​