The problem with not having much tax income is that you won't have anything to fund the research produced by new labs, and without research you fall behind the other civs.  Growth is important, but you can't keep colonies at 100% approval forever without securing more morale resources or building more morale structures.

Generally, take whatever resources you can reasonably defend.  You can get the rest in due time.

I tend to fix the tax rate based on the current treasury level, the rate of loss, and the urgency with which I need production to be done.

While your civ's economy is most efficient running at 100% production, if you're losing money fast then it may be wise to trim it a bit, just until colonies start to prosper.

Basically the idea is to get to the next milestone without the treasury running out and going into the red.  A milestone like finishing the current batch of economic buildings.  So by adjusting taxes and production it is possible to make it last that long.  Divide your current treasury by the amount of loss and that's how many turns it can last (assuming current values).

Building economy buildings is vital to your economy, but during the building they cost you money (social production must be funded).  Stagger your building projects and you'll avoid nasty dips into the red while still growing your population.

Military resources are game-winning, but economic and morale resources help you to afford a military to begin with, so I would say that there is a bit of interdependence.  It is possibly to do without any of them but the game will be much harder.

Well I play modded GalCiv so if I don't build labs I have hardly any research going.  I try to concentrate labs on colonies with bonus research tiles but any planet with five open tiles (so PQ6 or better) is fine.  That allows for a bare minimum of four labs and a Research Co-ordination Centre.

Because research is affected by bonuses from economic starbases, it does make sense to specialise a particular cluster of planets in research, although the same bonus will also affect planets which specialise in shipbuilding so there's no harm mixing them up.

Economic buildings on unspecialised worlds are low maintenance and don't directly benefit from economic starbses (it does help to speed up construction on tiles) so they're suitable for filling in the gaps when you don't really have a lot of income coming in.

It is sometimes useful to respecialise a planet, for example if you capture planets with intact research or factory buildings, you may need more income to run them.

Thanks MarvinKosh and jecy99 for your detailed replies - I played the game intermittently from 2005 (?) to 2010, so it is just a matter of remembering what I have forgotten.

After trying another couple of early games to test things, this is what I think - Continually adjusting the tax and production sliders is the way to go. Why? Because situations change. There is a high PQ planet available? Crank up the tax rate to recover the money spent on buying the colony ship. Have a few planets with small pop and you are not in red? Lower the tax rate to get 100% approval and watch your pop explode.

In short - yes, lowering tax rate to get 100% approval (on planets that need it) is worth it, even without Super Breeder, provided you can afford it. Just be sensible about it. For example, if your capital has 10B pop while the others have 1-2B, there is no need to lower the tax rate from say 45% to 39% to get 100% approval in your capital. Focus on 100% approval in your other planets.

Do you guys agree?

Yes, that is also good, but on larger maps or with too many planets I don't prefer to micromanage that much. When I have nothing better to do other than cranking out constructors, I go for high research/social spending.