I started by fitting the prop and spinner.  Then I installed the fuse top skin and baggage door to ensure the spacing would all be correct when I installed the cowl.  Then I installed the hinges as per the plans...  Now I was ready to start on the cowl itself...

I measured 2" back from the firewall and drew a reference line on the skin for use in determining where to trim the cowl, then I laid the cowl on the fuse and  prop extension...  I used a block of wood to hold the front of the cowl up where I thought it should be, and used a 1/4" spacer to hold it back from the spinner as per the instruction manual.  In hind sight I think I would use an 1/8" spacer instead of 1/4" because my gap ended up slightly wider than the 1/4", but it doesn't look bad...  I then used the reference line on the fuse to mark where to trim the cowl.  The first few cuts were scary, but after a while it got better.  Just remember to cut things long and work your way in.  I ended up taking to big a cut a couple times and now I have some gaps to fix.  But by the time I got to trimming where the top and bottom cowls meet, I was right on with the cutting...  Once I had the top trimmed to my satisfaction, I put it back on the fuse where I wanted it and drilled it to the hinges along the top of the firewall.  My rivets will be about 1 1/8" apart throughout the cowl installation...

I have a trike so I had to cut a 1 1/8" slot in the bottom of the cowl to accommodate the nose gear.  The plans didn't say how far back to cut the slot, but mine ended up right at 12".  Once I could get the cowl on all the way, I used a strap to hold it in place to see how it fit...  Not too bad, but the front needed a little work.  So I took both cowls back off and went to work on the front.  I had to trim off some of the prop opening flange on the bottom or the hole would have been oblong.  Then I used a file and my Dremel with a small grinding stone to clean up both cowls where they come together at the prop hole flange to make them fit perfectly, and marked where the holes would go for the nutplates and screws that will be installed to hold it all together...  Then I did some trimming on both cowls at the outsides where they will meet (outside edges of the inlets) so they would meet up flush.

Next I clecoed the top cowl back on and used the strap again to hold the bottom cowl on.  Once I had the front fitting exactly how I wanted, I drilled two of the 3 holes on each side of the prop hole flange to hold it in place where it should be.  Then I went to the outsides of the inlets and worked those until they fit perfectly.  Then I made those little aluminum thingys that you put on the outside of the inlets to hold them and the hinge pin in place, and drilled and clecoed them on to hold the sides in place too.  My thinking was that I wanted the front to be exactly where I wanted it before I positioned, cut, and drilled the bottom cowl... 

NOTE:  I have not done any trimming of the sides where the two cowls meet and the bottom cowl is still overlapping the top cowl by about 2", except for right at the front where I trimmed them to meet at the inlets...

Now that I have everything where I wanted it, I marked where the bottom cowl needed to be cut, took it back off, and made the cuts...  I got lucky and the first cut was right on...  I used an 18" body sanding block to clean and level the cuts and then put it back on the plane.  It fit great, so I clecoed the front back together, and started drilling the bottom cowl to it's hinges...  Be careful when drilling the bottom corners that you don't push or pull them so far up that they do not conform to the bottom of the fuse.  There is no support right in the corner and you can mess up right there, ask me how I know...

Once I had the bottom cowl drilled to it's hinges, it was time to mark and cut the sides to meet in the middle...  I used a light in the cowl  to mark where I needed to cut and then took it back off and made the cuts...  While I had the cowls off I also drilled and clecoed the hinge to the top cowl...  Then it was back on with everything again to check, then back off for final tweaking and sanding, then back on for drilling.  I did use a strap to hold it in place while I was drilling, but it wasn't that hard to hold it all in place...  The right side is off just a hair, which will be ok because you will need a gap for paint, but the left side is perfect all the way down, and I will have to use the sanding block to open that gap up to allow for paint before I do paint.

That's as far as I got in two days this last weekend.  I still need to do some shimming, and filing of the hinges on the top curve of the firewall before I can finish.  I plane to use the excess cowl pieces for shims and glass them onto the inside of the cowls and will use Pro-Seal to bond the cowls to the hinges before riveting...