My general approach is to keep the production slider on 100% and keep all planets working. I'll take care of the money somehow.
In my current game (Drath, immense, crippling, TA 2.02) that strategy failed me. One of my problems was that I didn't know about the financial windfall the Drath gain from other civ's wars. I didn't start the fighting nearly early enough.
At one point I could build both Industrial Sectors and Discovery Spheres, and I did, every chance Igot. Soon My enormous treasury was plummeting. I was running a deficit of nearly 3000BC per week. I could see financial ruin in my near future.
The only solution seemed to be to back off on my 100% production slider. But that seemed wrong, The reduced production and research weren't so bad but reducing production did nothing to reduce maintenance. I needed a way to reduce both output and maintenance. The answer was Research Academies and Manufacturing Centers.
An Industrial Sector (IS) produces 12 mu at a cost of 10BC. A Manufacturing Center (MC) produces 10 at a cost of 6. So if I was going to reduce my production to 83%, I could instead build MCs to replace the ISs. I would save the same thing on production but save an additional 40% on maintenance. Same for Discovery Spheres (DS) and Research Academies (RA). The DS get 16 tp for 12BC vs. the RA with 12 tp for 8BC. That cuts back 25% on output and 33% on maintenance cost. Planetary tiles with bonuses would get/keep the IS and DS.
I soon had my deficit cured and as my planetary populations moved into the 18b to 20b range, the economic woes were behind me, but I stayed with MCs and RAs and a 100% production slider.