Here's a link for temps, but if you don't have an accurate digital display (and I doubt you do), you have to judge by the state of your leftovers (light to medium brown, not black). If you have a cheap digital box, only use the numbers on display for a reference point. CA NORML Health Information

It would be helpful to know what vaporizer you're using. Using a conduction vape (globe type usually) is different from the preferred convection vape, and they vary in use from one to another too. How much to use is part of the learning curve and depends on personal preference as well. Using a lot in a whip vape makes for quite a few nice hits, but you also have to stir more to get it all vaped, and the hits at the end won't be very tasty.

Here's a video that may answer your questions.

YouTube - Vaporizers 101