My MYOG experience is with an EPIC encapsulated fabric that is, I beleive, about a 2.2 oz fabric. I got it from OWF about 6 or 7 years ago. I made it into a pair of pants for backcountry skiing. I have found it to be quite water repellent, windproof, fairly breatheable. Not waterproof. An excellent winter shell fabric, probably more limited for summer usage. Given the nature of the fabric - each individual thread is encapsulated with silicone prior to weaving, as I understand it - I doubt the different fabric weights have much effect on water resistance. Durability would be the main difference, I expect.
I also have a Black Diamond tent with EPIC canopy. Surprisingly rainproof, given how the pants perfom. That fabric is supposedly 1.7 oz, so might be the same as the 1.7 that OWF sells. Feels pretty fragile from the standpoint of an outerwear fabric.