I am in the middle of learning all about Dynavap, spending more cash than I should, but it's addictive and very interesting - compelling!
This is just my opinion - I am still learning
I only use an IH, the brilliant VapOven.
I have two tips, 2020M SS and the Titanium and two caps Standard and Low Temp, this is how they seem to me:
My favourite: Titanium tip, low temp cap - really slow build up, evolving flavours over maybe a dozen or so very very light tokes, zero lung burn, it's super cool flavour rich invisible vapour at the beginning and just light wisps as it warms up, by the end of the session I am very comfortable. This does not release all the volatile compounds unless you start going way past the click - not a risk I want to take with the low temp cap.
I leave this for a while, then switch caps. This enables me to finish off the AVB in two much bigger pulls and release all the remaining compounds.
This is completely different to starting with the titanium tip and the regular cap. This gives full extraction in 2 or 3 tokes, super tasty - you are basically getting everything at once. This is too much for me, although I do really appreciate why some people really like this.
With the SS tip, I find the low temp cap a little annoying because of the relationship between heating cycles and the way the tip behaves; the SS ends up being too hot and doesn't cool down enough each cycle like it does with the titanium. I may still have something to learn here, but it is my least favourite combination.
SS tip and cap - this is the most utilitarian of the four possibilities - it works, it's good! There's room to play around before and after the click, it's very good and probably the hottest combination.
I don't know if this is helpful or not, but if you are burning your lungs taking big hits, I would suggest easing off and taking your time, keeping the temp much lower, counting your heating cycles, don't wait for the click, just count 3 or 4 seconds each time to emulate the low temp cap.
Stems are a different matter, I would suggest glass for the cleanest flavours, but I really like wood for the low temp cap ti combo.
And yes, glass bubblers are great at cooling, but again, if everything is too hot, why heat it up that much? Stick to lower temps to start with.
Sorry, I wrote too many words and I am not even sure they are that helpful, but they are here now, I may as well post