Everyone has their own playstyles, so there isn't a wrong number for pop as long as it's high enough to supply transports and assist in production.
Snathi Prime (my homeworld) currently has a max pop of 64.5 and an actual pop of 32.1. My other planets have lower max pops, averaging about 30 each. I plan to take them all higher when I get more terraforming tech going. It can't go much higher without the Ultra Terraformers, so I think we're all going to be limited to less than 100 per planet. Growth is painfully slow so far and I can't seem to queue up birthing subsidies anymore. I'll have to adjust my tactics to compensate.
I rarely build morale buildings and when I do, I only keep them for as long as I need them. I prefer to have my morale boosters on starbases. Late game, I no longer need those either and can maintain 100% morale with the malevolent ideology trait.
For ideology, I try to build all 3 buildings on each planet. I can't do that with about 10 percent because of low PQ. We have to be more careful how we build out now.
I still have specialized planets here and there, but the vast majority now are factories and farms. I keep my global wheel at 10% econ, 45% each for manu and research. That means I'm running a constant deficit economically. With the Snathi, I'm actually gaining bcs per turn from their scavenging ability. They became my favorite race, easily displacing the Thalans. I might go back to 50/50 manu/research.
