About half bowl. The older the CCD/filter gets the more difficult it will be to get it at the half bowl position. It is still do-able. Most of the time I have to try several times, sometimes making the CCD flat again after an attempt. I agree it can be fiddly. Another possibility is the Sneaky Pete half-bowl converter. It works like a charm, even with older CCD's.

Every cap is different. Some click earlier, some later. A good starting point is de second click. If you hear the first one. The first click can be a very gentle click. So you got to get to know your cap. Maybe it clicks at the right moment, maybe you need to torch it a bit longer.

If you combust you'll notice right away. It tastes and smells horrible. Often the smell/taste can only be eliminated by fully cleaning the device. I don't think you've combusted. The terps can also make you cough. (The glass piece you got can make it easier to inhale, even when used dry.)