to minimize lag on 1.9 in spawn im proposing the following idea
spawn chunks have one tower in the center
with a train station and roads at ground level 4 lines and roads going directly north, south, east, and west in a completely straight line, with an elevated 3 line rail above them, if we make the roads 5 wide with columns in the center that gives us enough space to put 3 lines with a 1 block separation an incoming, an outgoing, and an express
with a portal to the original world on the 2nd floor
with a nether portal in the basement for new netherhub
surrounding this tower in all the loaded spawn chunks (chunks that stay loaded 24/7 wether or not someones in them) a natural park filling the entire spawn chunks, lit so no agressive mobs spawn
building any spawn city buildings, homes, embassies, public storage, post office, in a city surrounding the spawn park
with a complete ban on building or mining in the spawn chunks aside from the spawn building and the rail system
once the 4 rails get outside the spawn chunks put in a station on each rail where the rail splits into 3 at the north
and south station, so that we end up with 8 rails going in all directions covering the whole area
make nether highway follow the same map as the rail lines, with a nether portal at each rail station
people can connect portals to the nether highway but they must go in a straight line to the nearest main line for the nether highway, less turns and twists with easier navigation
im open to suggestions for modifications for this plan, but i think it will minimize lag for all of us, as well as making travel easier both by foot, by rail, and by nether highway