I think if you give me 1 CPU I can get ~13 energy profit (as of right now, it varies). This is based on predicted
income - cost and adjusted for measured
income - cost. The difference is usually pretty small.
Put in a lot of sums and that works out as ~12 WORK/creep for maximum profit. 7 extra work costs me ~0.6 energy/tick and saves me ~0.12 CPU/tick, so you can see it kinda works out. The marginal cost on adding an extra 2xWORK, 1xMOVE is ~0.17 energy/tick, ~0.012 CPU/tick saved, so not worth doing at 13 energy/CPU (but would be at 15 energy/CPU). This assumes spawn time is not a consideration which is generally true either on shard 3, or at high GCL.
Assuming this code doesn't have bugs (obviously not a certainty) I think it's reasonable to expect people to have at least 10 work/harvester in remote rooms, halving peak decay to 2.5 energy/tick. Going to 15 work/harvester would cost ~0.4 energy/tick/harvester, and save ~0.8 energy/tick on the warp container, so I'm pretty sure that given I'm already nearly there that's a no-brainer. Going to 20 starts to hit diminishing returns (0.4 energy/tick for larger harvester, ~0.4 saved on the warp container) so stopping at 20 is probably reasonable.
Now with 20 harvest/tick I don't actually need the warp network online all the time. Exactly how the "online" method works isn't clear. Seems like 1 energy/tick while online for the whole room. I probably only need it online 1/3 of the time as I can clear a source in under 100 ticks, saving ~0.67 energy/tick.
So we're getting to the stage where a 3 warp container room with spread sources will cost 1.5 energy/tick (container maintainance) + 0.33 energy/tick (activation cost) + 2.5 energy/tick (harvest intent decay) + 3.6 energy/tick (harvesters). That comes to ~8 energy/tick and ~0.15 CPU/tick for two sources throw in a reserver, road maintainance and other random intents and maybe we can call it 10 energy/tick and 0.2 CPU/tick. This blows my current energy/CPU out of the water - I can get ~4x the energy per CPU spent if I use 3 warp containers/room naively.