I just finished my cowl a month or two ago. My tips would be:
1. Don?t cut anything before you know exactly how everything fits. (Upper cowl, lower cowl, cowl cheeks, clearance to spinner, centerline, how it lines up with lower fuselage, how the upper and lower cowls fit to each other.
2. If you don?t have a laser level ? get one. I bought one at Sears ($29 or $39) that sits on a camera tripod that was great for shooting straight lines on curved surfaces.
3. Read the instructions ? but only as a reference. If I would have followed the instructions to the word ? I would have been very disappointed.
My cowl had a twist in it that made it extra hard. I spent several days lining things up, taping the cowl in place, using a laser level to check the edges, etc. before cutting anything. It saved me from cutting the twisted edge way too short. In the end, it came out nice, but it took forever. I had to heat the areas by the spinner and reform them. I had to do a buildup on the front edge to make it match. In short, it took far more work that I expected.
Hope this helps,
Cameron Smith RV4 #68