I made my own WH splash recently.
I started by adding 6 drops of glycerin to the 250ml WH (14% alcohol), 10 drops Tea Tree, 15 drops Peppermint & 15 drops Lavender essential oil splash. This didn't really have much obvious effect, so I doubled it for the next shave.
With a dozen drops I still couldn't detect any glycerin, so before I used it the next day I added another 6.
For me 18 drops of glycerin in 250ml of this concoction was just right - I can feel a certain slickness to the splash, and a hint of viscosity, but it isn't oily or cloying.
The splash works a treat. As far as I'm concerned it's better than my old stock Proraso green splash in feel.
I spent around £20 to make the first batch, including 2 new plastic bottles with nozzle screw tops, but the good news is that to make further batches I only need spend around £8 for a 250ml bottle of witch hazel.
In comparison, 100ml of Proraso retails for around £14 excluding delivery.
I would recommend people try making their own WH based splashes.
Just make sure you patch test all the oils first, especially Tea Tree oil.