I've been reading this forum for awhile now and am impressed with all the good information, now I have a question. I am installing a new range hood [wall mount] and have a question concerning the venting: My hood is a Pacair sp model [designed for Chinese cooking-lots of stir fry and grease], it is going to be vented out the back wall through the rear mounting cut out on the hood. The ducting will only be the length of the wall depth because it is going straight outside. The cut out is 3.25 x 11.5 but there is an extension coming from the blower compartment that runs through this cut out about 2 inches past the cut out, because I only need ducting the depth of the wall, my wall cap will probably attach directly to this attachment.The wall cap is 3.25x10. The attachment is 3 1/8x9 3/4 can I just connect the two [wall cap-attachment] with duct tape? Or is there any other options, does this setup sound like it will work?