I have a classic volcano. I've found that starting out around 345°F to 360°F for the first bag and gradually increasing up to 375°F works well. The last bag I'll bump up to just over 400°F to get the CBC's / CBD's. From what I've heard, THC vaporizes as low as 300°F, but I didn't get good results when I tried it that low.
When the herb is fresh, I can get 4, sometimes 5 bags. This time of year I'm vaping from last years harvest, and I'm getting 3-4 bags. I have the solid valve setup & make my bags a little longer (30-32") than the pre-made ones.
The good thing about the volcano is it's easy to use & real hard to fuck up. It's the only vape I've used (and I have 3 different ones) that's similiar to smoking.
You didn't say whether you had the "easy" valve or the "solid" valve setup. I only put 1/4"-3/8" of grinded buds in mine, about 0.2 gram (instructions say 1/8" to 1/2"). If you're filling it up, you may be wasting bud. You don't need to grind it all that fine either. After the first 2 bags, you should re-grind the bud though. (Now if you're using a portable vape, you need to grind the living shit out of it.)
I've smoked since 1967 and I'll tell ya, this volcano is one of the best investments I've ever made. I only wish I would of got one years ago.
One more thing, save your vaped weed & make edibles. Find out how on the edible page here.
Congrats on your new "toy". It should last a long long time.