What do you cut with? I have huge Swiss made shears, originally for cloth, razor sharp, for big parts,, and around 20 different scissors, for other parts, a lot that have curves. Your edge lines are wavy, and that gives fitment problems. If you were painting the model, you could fill it with filler, but when relying on gaphics, you need to be precise. Of course, the end of the Impulse piece could be made perfect with a thing piece printed out, the glued over the existing one, but carefully cut out. Not knocking your model, it's just that the rest of it is so awesome, you may be working too fast, or have to revisit how you cut stuff. I rarely use Ex-acto blades because I can't get a straight line out of them (old fart syndrome - "OFS"). You want it too look great with the lights on too!! When you are done, these ships, lit up in a blacked out room will be awesome, especially if you have some of those fake planets they sell, hanging in the background, and some irredescent tiny dots of different sizes on the walls, to look like stars. Some dry ice, and you have a Nebula, and ..................................................
