I just completed having the map generation code take the "Starting Area Size" setting in the Map creation UI take effect. The map generation code modifies Factorios map settings to make each base playable and not completely overrun with biter bases. It sets up three zone.
Starting area is 6 chunks - a chunk is 32 tiles (turn on the grid in F4 to see this) - no nests in this area.
Next zone is starts outside 6 and goes to 12 chunks
Final area - Danger Zone - starts at 24, previously it was 30 and in Oarc is normally 32. I did testing to see what is appropriate and 24 is right.
When you play DeathWorld (75%) - this tightens up from 6,12,24 chunks to 4.5, 9 and 18.
If you want the old 30 tiles - set the Starting area to 125%.

The map generation modifies the biter nests so that in the second zone 5% of the nests are kept, and only small nests will be in this area.
In the Danger zone, 20% of the nests are kept and only small and medium nests remain.
Check my extensive list of screen shots in my discord to see what this looks like in a deathworld and normal game at 75%.
Just for fun - give 17% Starting area size - you'll have biters in your main area!

Removed the name in base while the player is online. Some have reported GPU issues showing the text shifting, and distracting. It will be placed back when you log off.