Squisher
Minister of Fire
It's common to use a corrugated flex liner the whole way, and they clean up really well espescially with rotary cleaning which I'd say is becoming more and more common. Possibly call around and see if there are any sweeps who do installs who might be able to give you a quote on installing a block off plate and adding insulation to your liner?
I wouldn't look to your dealer for anymore advice. From the things you've mentioned he is grossly misinformed.
I wouldn't look to your dealer for anymore advice. From the things you've mentioned he is grossly misinformed.