Looking for new insert to replace aging VC Winterwarm large.  Most I am looking at require 6" liner but my VC required 8".  In 2002, had new 8" double wall Duravent installed by the stove shop.  Could I leave the 8" in place and simply slide in a 6" SS flex pipe??  As the Duravent is double wall, I should not have to insulate the 6"?
	
		
			
		
		
	
				
			 
	 
	 
 
		 
 
		 
 
		