So, you've stuck with the same loaded voltage output, 3.2 V, but I don't know what resistances you've tried for your atomizer. (I'm using "atomizer" generically here, I don't really care if you are using an actual atomizer, a cartomizer, a tank, or a MAP tank.)
The resistance is important part of the equation. Two things increase TH consistently, Nicotine Strength and Power. I am going to assume that you've maximized your nicotine strength to 36mg to get the TH you are looking for, so that leaves power.
The nice thing is that you've given enough information so you can easily find the power you're at now, so you can adjust it up. P=VI (Power in Watts equals Voltage in Volts multiplied by Current in Amps.) Since we are only have atomizer resistances we can change let's take V=IR, do some algebra so we can take Current out of the power equation and we have I=V/R. We throw that in place of I for the power formula and P=VV/R (Power in Watts equals Volts squared divided by Resistance in Ohms) Since you are using batteries that have a 3.2V output loaded, that's easy, but I will just guess that you are using a 2.8 Ohm atomizer, just as an example. P=VV/I=3.2*3.2/2.8=10.24/2.8 = 3.66 Watts.
If we were to use a 2.0 Ohm atomizer then your power goes up to 5.12 Watts. If you went down to a 1.5 Ohm atomizer your power goes up to 6.83 Watts. As power goes up, so does throat hit, TH. To get higher than 6.8, you will have to increase your voltage. Since voltage is squared in the power equation, it has a much bigger impact than resistance.
Good luck in your search for a TH that will work for you. I'm sure you will find it soon.