Are you clear-coating AFTER you install your canopy? It looked like that's what happened on your SBD, that you shot it with Dullcoat, hence the frosted look.... In a word or three, don't do that... Don't Glosscoat it either... If it fits ok, I just hand-paint the frames and attach with white glue after everything's done.. If you have to do a lot of work to blend it in to get it to fit, well... That's another animal..
As for your skills... Well, the only way to develop those is to BUILD, lol.. And using the streched sprue for antenna is probably the easiest bit of scratch-building one can undertake as a beginner... Go for it... Just be sure to get it REALLY thin in that scale... No more than the diameter of a human hair... Also, you don't have to glue it in place as a tight-wire.. A little slack is ok. Just, once the glue is dry and cured, take a heat-source like a freshly-blown out match, soldering iron, incense stick, etc, and move it close to (BUT DON'T TOUCH) it and when you reach just the right distance, it will suddenly snap tight...
The next step would be to try to scratch-build a simple cockpit.. You just cut away the solid area and with a little sheet styrene you can easily build a floor, sides and a panel & seat... Another piece of stretched sprue and you got a joystick.. If you want, you can cut paper patterns from index card for the sides, floor & bulkheads, then transfer that to the sheet. In that scale however, you can eyeball easily enough, and you don't need a library of refs either..
Suggestion, rather than duplication, is the force behind "Creative Gizmology" and simple scratch-building..
Once you start doing it, you'll get hooked, I promise ya.. And this is the best part.. The more you do it, the easier it becomes, the less you'll feel a need to rely on after-market parts to make the old kits look great, and *gasp* won't be spending ridiculous amounts of money on over-priced, over-engineered "New" kits, and then MAYBE some manufacturers will MAYBE get their acts together and get the prices down from "Un-farking-believable" to at least "Tolerable"...
One of 'em might even release a a1/48th scale 25-30.00 PB4Y...
(Hey, I can dream...)
At any rate, keep Hammering (get it?) away at 'em.. You'll build more than just a model.. You'll build confidence in your skill-sets, and that's something that not everyone does...