I started with Brantel's helpful description of how he did his:
http://www.vansairforce.com/community/showthread.php?t=35100
But then I deviated... my hangar partner, a professional surveyor and eternal student of how stuff fits together, objected to the plans approach of fitting the top cowl first. He argued that it made more sense to start with the bottom, since the lower corners of the fuselage define exactly where the back wants to be, and the spinner takes care of the rest.
Since I was planning on a constant speed prop, I bought the prop and installed it with the rear spinner bulkhead, to provide the front cowl reference. I settled on 1/4" as a reasonable cowl to spinner clearance based on experiences of locals, and so used some pieces of 1/4" thick plywood plus some of the spring clamps left over from my Sika canopy project (should have bought stock in the company that makes Pony spring clamps).
I'm using camlocs, not hinges, but the method should be the same. I used a ratchet strap to pull the lower cowl up to the engine, and used the plywood spacers and spring clamps to suspend the front of the lower cowl where it needed to be. I'm gambling on no engine mount sag (can shim later if need be) so I centered everything. I used the plans approach of drawing a line 2" or so back from the front of the firewall, then measuring forward with the cowl installed to locate the cut line on the lower cowl. Of course since I'm building a straight -7, I had to clearance the lower cowl for the gear legs, but that was easy and self-explanatory.
It was pretty easy to trim the lower cowl accurately to the firewall using a cutoff wheel in a die grinder, followed by a piece of sandpaper glued to a long piece of aluminum square tubing used as a sanding block.
Next, I mated the upper cowl to the lower cowl, using, among other things, a disc of plywood cut to the 13" diameter of the spinner. Here's where some of Brantel's fitment advice proved helpful. But because my upper cowl's initial fit to the lower cowl was so crappy, I had to do a lot of cutting and heating/bending/shaping to make them talk to each other.
OK, I have been reminded that it's my turn to cook dinner, and if I want continued support of my project, I'd better get busy.
Here's a link to some photos I took during cowling, inlet ramp and oil door fitment:
http://www.smugmug.com/gallery/13464009_wiQ9w#912835353_YR8Xe
