I wrote something similar to this originally to save me pounding a calculator whilst I was testing the drops and current limits on the VapeShield project. Although what I was measuring and calibrating there was different to this I realised the code could be easily adapted to be a handly Voltage Drop checker. After noticing the birth of this section I thought it may be useful to others, so I just re-wrote it in that context.
So here it is. The main EXE is in the zip file along with the source code so you can check and compile it yourself if you're worried about running EXE files from strangers. This as written in VS2012 C# so you'll need .NET4.5 installed to run it.
Make sure you know the level of the battery, the battery internal resistance, the resistance of the tank-o-meter and the resistance of the atomiser you are using. Enter these values into the relevant textboxes on the app.
Attach a tank-o-meter to your mod with the atomiser and fire the coil up. Take note of the tank-o-meter reading and enter that into the app.
The bottom three boxes will now display what your tank-o-meter should read if your mod was perfectly conductive, the amount of volts you have dropped over what is expected, and the extra resistance your mod appears to be introducing.