It depends completely on the DC fast charger and how aggressive it is. That's not how it is suppose to be, the car is talking to the QC and telling it how much power to send, but I've noticed that depending on the QC network you choose, that can very greatly from "cautious to melt the battery" as far as how fast it will charge. It is true, most QC will ramp up power past 20% and then after 50% you start to see it ramp down slightly and then quicker the closer to 80% that it gets and beyond.
The first annoying issue I've noticed at QC is that whatever max they have in power output, they gauge that for the ramp up and ramp down. So even though most of the QC will advertise 50 kW, they may only have a 40 kW or 45 kW true max, some as low as 30 kW (*cough* Nissan Dealerships *cough* ) and thus seem to take a long time. Unless you have a lot of different QC networks around you to compare, you'll never notice this at the same QC you visit all the time.
Example, Electrify America, seem (at least where I am) to have super aggressive QC stations. I can bring my 2013 Leaf at 72F battery temperature, say 20% charge and do a QC session that will hammer the battery with 50 kW all the way to 80% and then continue 20 kW all the way to 100% and the battery is sitting at 110F. If I were to duplicate the car conditions again the next day at a Blink QC, same battery temperature, charge level, etc. It will only max at around 44 kW and well before 80% it is already down to 20 kW and finally finish up at 6 kW to top off at 100%, thus taking a very, very long time to finish. But.... the battery temperature will only be raised to 90F for that session, thus probably less wear and tear on the battery.
For your situation, I would recommend enough to get from one QC to the next because as the battery temperature keeps increasing, you notice lower and lower charge power each time. You also don't know how aggressive one QC to the next will be and thus you might spend a lot of time at a QC if it has a very "cautious" approach to battery charging when the temperature is higher.