Im rank 450ish.
Which would be better to raise my production?

Taltherian, obviously.

If you have a few 15x+ planets it might be better to be litheor, reason being is each time you place a probe on a 15x you get 27 extra ap, (2*6.75*2). In order for you to get more ap from being talth you would need to have a planet with 54 ap from structures, which can be achieved on C planets like plasmas/dysons or if you maxed sized and transformed gaia/crystal/ocenaics/irradiated/sentient. So if you only have a handful of planets maxed out it is better to be talth in the long run.

The probes also help with cloaking your best worlds - two probes give 300 cloak, plus various bonuses.

Probably talth.
Untill you have a decent amount of maxed planets talth will be better.

take a planet like this one Very Large Terra Planet,
Mining Rich 12 units/hr (3 production from structures)
Artifact Mega Rich 180 units/hr (30 production from structures)
Research Extremely Rich 35 units/hr (7 production from structures)

with Litheor you could change the 2 Space Elevator Artifact: 1, Population: 50
to Size 1, +2 Artifact/Research/Mining, +900 Pop, +150 Cloak

that would increase production to 7 / 32 / 11 and add +1700 pop and +300 cloak
and would give 20 minerals pr hour, 192 artifacts pr hour and 55 recearch pr hour (+8 minerals, +12 artifacts, +20 recearch)

or if you instead go for the Interrogation Stronghold (size 1 Research: 2, Defense: 300) + Sha'din Hypergrid Network (size 1 Research: 2, Defense: 200)
it becomes production to 7 / 34 / 7 and add +1800 pop, +300 cloak and -500 defence
and would give 20 minerals pr hour, 204 artifacts pr hour and 35 recearch pr hour (+8 minerals, +24 artifacts, +0 recearch)


if you instead use Taltherian ability to increase it +2 in artifacts you will get
production to 3 / 30 / 7 but with an extra +50% bonus in artifacts
this will give you 30 * 3.50 * 20 = 210 prouction in artifacts (instead of the old 30 * 3 * 2 = 180) or (+30 artifacts)


so depends on what you want to do
if you want to make your planets harder to scan and increase all 3 production types litheor is a god race for that, and you max out a planet after only 80 houres and can then move on to the next (and if you play as Govenor, you also have increased chance get planet events witch could give you, Lush Biosphere, Subterranean Caverns, Small Moon, Planetary Rings, Large Moons, Advanced Civilization Ruins, Stealth Screen or Reactive Barrier)

but by the time you unlock litheor, the only production type that will really matter to you is artifacts. As Taltherian you are not limited to 2 boosts pr planet, but can take it all the way up to x15 increasing your artifact production quite a lot once you have boosted all your good planets


Both races are great.
you can putting the probes on 5-10 planets as litheor and then going Taltherian to max out the artifact production on them or max out 10-20 planets as Taltherian and then go litheor to put the probes on them

but as I see it, theire are a lot off other structure upgrades out theire, Gift of the Mind, Perimeter Station Upgrade, Trellith Comm Relay Upgrade, Hypergate Upgrade, etc etc etc Heist Dispatch Center + Heist Dispatch Station Upgrade (Galactic Concord Station + HyperSensor Satellite + Isolation Bureau) you can use to increase the basic production score on your planets, so in the long run you are better off as Taltherian