I have a very sensitive lungs (severe chronic lifelong asthmatic) and have found that mouth pulls and degummed hemp fiber filters create a very smooth, cool, non irritating vapour.
Take a few inches of degummed hemp fiber.
Moisten one end and wind it like you are preparing to thread a needle. Place it between your thumb and index finger and wind it round and round between your two fingers to create a flat round filter.
Stuff this into the bottom of your bowl. This filter will effectively remove any tiny particles that may otherwise get through your screen and into your lungs. It also keeps your condenser surprisingly clean and clear of debris.
The mouth pull technique provides a cooler fresher vapor inhale. Dial down to a tight air restriction and cover the carb for most of the toke. Pull the vapor into your mouth without inhaling, like you would when puffing on a cigarette or cigar. Near the end of the pull, open or feather the carb to bring the last of the vapor into your mouth along with that pulse of fresh carb air, then open your mouth, remove the Vapcap and inhale the vapour and fresh air into your lungs. Exhale. Repeat.
Use a filter. Take short mouth pulls versus long tokes and incorporate fresh air.
This technique, for me, gets me where I want to be with no lung irritation. It is the smoothest, coolest vapor I have ever experienced in a vape. Because of this and all the other inherent characteristics of this ingenious device, my VAS is now only focused on Dynavap parts and accessories.
I have zero desire to try out any other vape. The Vapcap checks all my boxes and then some.
If you experience lung irritation, try this technique.