With the V2.5, I found that you did not get good draw or vapor unless the cans were filled. I have heard that with the V3 you can now use partial fills and still get a satisfying session, due to the new stainless steel lid. If youre using concentrates, a little dab will do ya. I havent used a V3 yet so dont take that as gospel. Im sure someone who has used one will chime in.
Ditto the full cans. I tried partially filled cans, and it worked, but not nearly as well as mostly full. I cannot fill the screens to the top because I want to leave room for the lid of the door when it closes.
I also tend to take mini sessions. Depending upon the temp, you can do this and not lose too much. It takes a while for the chamber to cool, so if I am using setting 3 or, more rarely, 4, I will switch over to setting 1 just before I take my last puff, draw long and slow, and then turn off.
There is, inevitably, a little bit of wasted toasting that occurs, but I have not found it to be a big problem. I mainly use the convection screens with flower, but as this is not a true convection vape, the chamber is warm and will vape herb until it cools. I do not find that there are wisps of vapor escaping my unit for more than a couple seconds when I use the dial down plus long draw technique.
Edit - I can ONLY speak to vaping flower, btw.
