Less glycol will definitely help if you're currently using 65%+. The conductivity of coolant changes quite a bit with glycol concentration.To be honest i have a slight problem with my cooling system. Everything is in tip top shape but the fan shroud is missing and i can't find one anywhere in stock new or not broken. Temp tends climb quickly in traffic on hot days. I have a 80c thermostat but it quickly opens all the way and electric fans kick in at about 95c. I'd like to know if a proper mix of 50/50 or even 40/60 would help a bit when the thermostat can't cope anymore.
Something else to keep in mind is that even if your radiator was able to keep coolant temperatures in the normal range with a high-glycol mix, the cylinder head and liner will run hotter at a given coolant temperature. This could increase the risk of knock and piston deposits, and could potentially increase wear by reducing the oil film thickness at the piston rings. Engine damage will occur more easily if the engine ever does badly overheat.
I'd use 40-50% glycol. Too little glycol could start to reduce engine efficiency by cooling the cylinders too much in normal driving. It would also reduce the concentration of the corrosion inhibitors.