Little off topic, but you've been able to reduce/eliminate placement lag caused by large/close by planets by increasing the scale of the maps?
Yes. The "placement" lag was caused by sins loading the gravity wells (placement grids) of ALL nearby planets within VISUAL range. By visual range, I mean you can physically see the planet mesh.
By scaling the maps to such a degree where you can no longer see the mesh of an adjacent planet, sins no longer loads the gravity wells of them when you are placing a structure at a given gravity well. As a result, there is no more lag .
To clarify, the problem started when we made the planets larger without increasing the size of the maps. This made adjacent planet meshes "visible" from other planets when zoomed in. If you ever noticed, sins will load those placement grids eventhough you aren't placing a structure at an adjacent planet. I hope this clarifies it!