Fitting the cowling and windshield is always a PITA, not actually hard just time consuming to do correctly. Be careful about ever getting any gas on that lexan windshield because it will craze and.... oh thats right, never mind!
I had real good luck with my last build, my current plane, with Gorilla Glue, believe it or not. Someone else gave me a heads up on it, and it sticks about anything to anything, 12 years later and over 2000 hrs flight time nothing has moved. From the Ace Hardware aviation department. Also from them, Ace that is, Lexal, a crystal clear adhesive caulk, that is specifically formulated to glue lexan to plexi, and about any other plastic. I have a plexi shield but a lexan skylight, and this Lexal was used at the juncture with great results. As the stuff is super clear and pretty much invisible, I also used it to secure various small wire runs, like my GPS antenna coax that runs up the door post, a few dabs of the Lexal, while holding position with masking tape, and a day later the tape comes off and the cable just magically stays there, great stuff. There is also a lot of JB Weld used in my plane, and again I have never had it fail me, modern adhesives of any kind are a real time saver and often better then mechanical means to secure something, though old timers may scoff and consider them half assed, I don't.
There is an old saying in building airplanes, maybe you've heard it before: 90 % done, 90% to go! All the last little details, after the big things are done, take a lot of time, hang in there.