What's the difference between combusting and vaping in terms of glass?
For combustion, you want glass with multiple chambers, more diffusion, Ice pics, etc. You want to physically cool the smoke as much as possible.
For Vaporizing, there is a point of too much diffusion in which you are robbing your hit of all flavor. You want to moisturize the hit. Any amount of water will help. Low diffusion helps with flavor. For vaporizing, you need to find the proper level of diffusion for your vape.
For many, that's a simple perc, like an inline or something else which yields less bubbles. My matrix perc on the GB-187-S provides more diffusion, but helps smooth out the flavor for the massive rips I take off my E-Nano