stainless steel liner questions

[wood butcher 13]

I am about to install a single walled liner for my wood stove insert. The issue I am having is finding an oval to round adapter. The oval size 4X11 and I am thinking of going to 6" round pipe.Reason being the round pipe is more reasonably priced, I am on a very tight budget. Any suggestions would be appreciated.

Thanks,

 

[pen]

What stove is this being connected to? What is the diameter of the stove collar? What are the dimensions of the chimney (interior length and width)?