[Ballbarian]

And yes, I didn't even know we HAD 138 GAN options - I'm assuming many were duplicates. Bit much if you ask me

Right now, there are 162 seperate gan files.
Some of those can appear in multiple flavors multiple times, but most are unique (only one placement ever per map).

Question: So, Do I add starting locations when creating the map or when semirandomizing? I'm not sure which options are for which. Does the "semi-randomize" button only work with those options on the front page (fiddle, fiddle xp, fiddle name?)

Starting location options should be set after you have a generated map (or an existing map). Or in other words, when semirandomizing.

In the following image, everything under the four tabs (General, Climate, Starts & AI Gods) are SemiRandom options that are only applied to the specified map file when using the "Semi Randomize" button.

If I have a 150 province map, with 9 nations and I have a 4 province buffer... will those 4 provinces in the buffer be semirandomized if they fit? Any way to prevent those 4 from being semi-randomized? Hmm, that wouldn't work, would just be a line essentially... how about any way to prevent randomization of any province adjacent to a capital?

Start locations and all of their neighbors are seen as off limits by SemiRandom. They will not have specials added to those provinces. This only works if you use SemiRandom's start location placement options.

22222
21112
21C12
21112
22222

In the above example, the Capital and all of the 1's, will be skipped, but the 2's could have special provinces assigned to them.

All the 4 province buffer does is ensure that at least 4 (or more) provinces exist between any 2 capitals. This also means that you could end up with less than the requested number of start positions. Always read the SemiRandom map description (in Dom3) as you are setting up a new game for the open start counts. This will tell you how many land/sea starts were placed. If you exceed these counts when adding nations, you risk placement errors and could even have 2 capitals start adjacent to each other as Dom3 tries to use the empty provinces that border the expected capitals for the extra ones.

So,
9 nations, 50% fiddle, 150 map
~4 adjacent per capital (36)
150 - 36 = 114 available to fiddle?
Possible or not worth the effort?

If I had a 150 province map, first I would decide on how many provinces per player I wanted. In your example (9 nations), let's say I wanted 16 provinces per player...

Next question would be, do I want any sea nations?
If the map was with no or very little sea, I would set "Max Sea Starts" to 0.

Now I would set "Desired Num Players" to 9 and leave "Enforced Spacing" at 4.

For "Fiddle Prov%" I usually use 100, but 50 would work just fine. Even 100 doesn't mean that every province will get fiddled with, but as the selection of gan files grows, it could in the future.

If you didn't want to mess with the start options, you can just lower that fiddle 50% and leave "Desired Num Players" at 0, but that could still leave voids where the lands were treacherous and civilization was sparse. You would only have about 8 clear provinces per player for possible starts in that case. A little too tight and risky for my tastes.