Keystoker 90 with duct ring in top from factory measurements

Anyone have a Keystoker 90 with the duct ring welded into the top from the factory? I am looking for dimensions how the factory welds them in, spacing from the back and from the front of stove. I called them but they are always a little vague like it's no big deal just cut the hole and weld it in. I am fine with cutting the hole and welding the ring in I just am a little fussy on getting it right.

For the EXHAUST or HOT AIR.

Mine is a Back/Bottom power vent. So the top is just open channel.

I modified mine for the HOT air, I cut mine own and just put a 8" sheet metal flange on it.
Keystoker Koker 160 Furnance Advice

Thank You! My chimney vent is almost where your duct ring is. This is helpful, still looking for the factory setup which puts the duct ring further forward. They just sent me parts, nothing else. I just get nervous cutting a hole in the top of a perfectly running $3000.00 stove. I will get over that and commit sometime soon.

Okay.....I thought the same thing about cutting mine too, but it worked for me. I have a 8" Duct pipe running upstairs and it helps.