Gary,

 

I used Stainless Steel 2700 Phillips Head Camlocs. However,  if you choose them consider

 

1.  My fiberglass cowl was flimsy so I added a 1.5 inch wide 1-BID of fiberglass around the inside edges of the cowl.  Later, in some high stress areas I added another BID of carbon.  If you cowl is of carbon fiber, I still would add 1 BID of carbon to strengthen the edges carrying the Camlocs or imbed dimpled washers (Tinnerman's?) in the exterior surface.

 

2. I spaced my Camlocs closer than was recommended, thus avoiding bulges between the Camlocs caused by escaping hot air.

 

3. Camlocs are spring loaded - thus, in high speed flight, my cowl shifts upward a bit.  I still get bug spatters on the top forward vertical cowl face - right behind the prop spinner.

 

4. If I had to do it over again I would use hinge pins (pullable from the cockpit) on the straight sides and screws on the bottom cowl/fuselage joint, all for cowl for rigidity - Camlocs on the top for easy access.  And certainly Phillips Heads to eliminate the "slipped screwdriver" scratches. 

 

5.  Hmmmmm... maybe a cooling plenum.......