So, 1 Refinery Hub + 1 orbital Commercial Outpost on a rocky moon with pristine resources without Biologicals would be better that 3 Refinery Hubs + 1 Orbis on a rocky moon with pristine resources with Biologicals?
"Better at what?" is the question here.
The Orbis is a much higher-population market than the Commercial Outpost, and you're giving it two additional Refinery Hubs to boost development level (and economy fraction, but development level is probably more important) even further. So for anything it exports at all, it'll export probably hundreds of times more tonnage than the Commercial Outpost (it really should, since you hauled over ten times as much to build it)
On the other hand, the Orbis is on a moon which adds Terraforming, and 3 extra hubs can only go so far to cancel that out, so it's possible that for the specific Refinery exports that Terraforming imports - Polymers and Semiconductors especially are very import-biased - the Commercial Outpost will end up with some exports of them and the Orbis will be importing them instead.
If you want maximum spread of cargo
and maximum tonnage for that sort of budget, then:
- on the one-slot no-bio moon, build a T1 surface outpost and the Orbis for
two huge markets at only slightly more than the cost of Commercial Outpost + Orbis (plus this way you get both orbital and surface refinery exports, rather than just the orbital ones)
- on the three-slot moon with bio - or anywhere else in the system that's convenient - build the three refinery hubs so you get the development level boosts and T3 points anyway.
(The refinery hubs are only generating weak links rather than strong links to the stations, but you probably won't notice the difference given everything else that's going on and the moon already providing a perfectly good baseline refinery economy)