Sulfate increases the perception of hop bitterness and makes the beer seem drier. If you add too much it will over exaggerate this and won't be as pleasant. You're looking to get a crisp bitterness without overdoing it. My palate says to keep it under 125 ppm, probably closer to ~100. Your palate may say to increase it a little more. I would never recommend going more than 150-160 ppm, but I'm sure some people do. As long as your carbonate levels are low, or at least in the lower range in RA for the color beer you are making you should be alright, just start on the lower end with the sulfate on your first batch and if it's not quite where you want it you can increase it a little on your next batch. Of course the total IBU's and variety of hop(s) that are used in your beer will also have an effect, so there is some balancing there that you need to practice. That's why it is best to start on the low end and work your way up.
Primary- Czech Pilsner, IIPA
Secondary- IIPA, BVIP, Doppelbock, Baltic Porter
Kegged- A whole lotta beer
On Tap- Helles, Pale Ale, Rye IPA
Next Up- BVIP, IPA