... if I should add this to my mini-machines mod lmao. Demand doesn't seem to be very high, but it might be useful.

Also, mind giving a brief explanation of how everything works now? The regular sized entities are like, 5x5, right? With the heat connections being at the 4 corners, and the middle of the 4 sides. If you make that a 3x3, then every single tile around it would be a heat connection. Do they connect to each other?

1x1 entity has one connection on the side, so on 4 sides it has 4 connections
2x2, 4x4, 6x6 entities have 2 connections on the side, 8 connections total
3x3, 5x5 (vanilla), 7x7 have 3 connections on the side, 12 connections together
Neigbour bonus will be added only for same size reactors, idk why, it's done so in engine of Factorio.
All reactors have same energy consumption, but have this area-based efficiency:
5x5 has area 25 tiles and have efficiency 100%.
4x4 has area 16 tiles and have efficiency 16/25 = 64%.

Hmmm, very interesting. Thanks for the info!