Well, I have built a few wood stoves in my time, so here is what I think.
First, it scares me alittle that the unit is so close to the siding on the building, but than I dont know what will be used between them, anyway, if you are planing on completely inclosing the stove, than I would reccomend a blower that would direct air from the floor area of your shop into the stove unit, and than just a different duct that would direct the hot air back into the shop at the highest area of the stove.
As far as using the copper pipe Im not sure why you would want to do that if you do not plan on have water in it?? I dont beleve you would ever get the stove hot enough to melt the copper, unless you had soder fitings, than of course that would not work.
I have built a wood stove that has 3/4 inch flex copper right in the fire box that coils around the 36 inch dia pipe line pipe that I used for the stove. I had a transfer pump that moved the water thru the coils, and into a heat exchanger in my shop. Of course you also need a expancion tank, and a pressure releif valve for this system, or it will go boom!!!! this unit used very little wood to keep the water hot. when I needed it.
I think for shop heat, you are on the right track, using just heated air with a blower, but make sure you eithe keep a air space, or some kind of nonflamable matl. between the wall of the building and the stove, I would hate to see you have to build a new shop. Ha.