On windows, slider doors, where the 16 in o/c furring "channels" don't completely go from grade to the soffit, how does one detail these areas so air can flow? I was thinking to leave a small gap between the vertical furring strip and the top/bottom horizontal window box out furring strip. Or perhaps have mini-venting at the bottom and top of the window but not sure how to do that without it being seen. Any tips? I am furring out the windows now and will start the vertical strips shortly - would greatly appreciate any advice.

Air flow is not critical; the air space is. Make sure the spaces over the windows is properly flashed; don't worry about actual venting.

What I decided to do was leave a small gap (3/8"?) between the top/bottom window pieces and the vertical FS. This way a little venting happens and no rabbetting is necessary. Started installing the 1x4s today. The headloks split them at the ends unless you predrill. Doing it myself I find it easier to predrill all the hiles and load a screw I,to each one, then hold it in place and drill it. Working well. In the last two days I've furred out all first floor windows and done the first floor of one wall wih the vertical strips.

on windows I'm making the top strip the RO length plus two FS widths, as a "cap" of sorts, the sides extend down below and the bottom FS is slightly less than the width.

I know you say venting isn't critical, but I'd like to have some venting. Has anyone "rabbeted" or grooved the front of the FS? The 1x4 is 3/4 think. I'm thinking about setting my circular saw to 1/4 depth and running across the face horizontally of the FS periodically, so the FS is still one piece but has micro channels between sections to promote cross venting (on the FS) above or below windows and doors...

Your on the right track you are doing better than house wrap by air venting to keep moisture from getting trapped or condensing on your cladding, just like attic venting osb. Look how cora-vent does their window details. The rabbit for cross venting sounds good as long as it does not compromise fastening the cladding. The big FS rain plane and air gaps can produce some pressure on it. Don't forget the bug screen :) http://www.cor-a-vent.com/pdf/cor-svb.pdf

Going to use ridge vent material instead of,bug screen or cor,a vent. Still installing furring. 3400 SF house and doing this myself will take some time. Making great progress though. Headlok screws are tough to find

GRK and similar screws from Fastenal do not typically split the wood. All are available online; Fastenal has stores across the country.

Fastenal Headloks seem to be half the price. I ordered some on line and there's a homedepot with two boxes to get me through the weekend. I have a box left so it will take me time to go through three boxes before they arrive.

look at the tip of the screw. Some of their screws (and all/most of the GRKs) have a very sharp "predrill" tip which incorporates a sharp knife edge and cuts the hole, preventing splitting.