yep, I know it's a bit overkill but it'd be nice to get something working.
BTW I only need a couple of drops of liquid for the refractometer...that's hardly a refreshing pint
The problem with refractometers is they don't work very well when you add alcohol, as alcohol throws the reading off, refractometersare good for sugary wort but once you start to make alcohol using yeast, you may as well throw the refractometer away.
You can use one but only by doing a very complicated mathmatical calculation, after taking a reading, & then its only an estimate.
For a truer reading you need to sample using a high end calibrated spectrophotometer , & that would be true overkill for a home brew.
Soldier on with your project, if that's what floats your boat, though I think you would be better to spend your spare time and money on acurately controlling your fermentation temperature, or sorting out a device to analyse your water additions etc it would be time better spent, I fear, & you would get a better tasting beer out of your efforts.