George (@gblair), the UV cure resin might work to fill in those window gaps if you're careful in applying it.
Today, I finally started installing the interior into the fuselage. I first wanted to get the windows in the cabin made using the low viscosity resin which showed up yesterday. Let me first discuss that.
I reasoned that I could apply Scotch clear tape to the exterior of the fuselage over the windows and then back fill them from the inside using small amounts of the UV cure resin. My hope was that if I could apply a small amount of resin, then the windows would be flatter and less prone to distortion. By backfilling from the inside, I also ensured that they filled out the window openings (more on this in a moment).
I tested one window doing this and it seemed to work okay. After it was cured, I applied Future acrylic to both sides (Pledge acrylic in some countries) and then let this dry. The windows have a nice glossy look to them and they did indeed fill out the test window opening flush with the exterior of the plane. However, there was still distortion. It appears that the windows are acting like a reverse magnifying glass, making objects further away look smaller.
Okay, so mostly encouraged by this, I went ahead and did the rest of the windows. A couple of things happened here which should be noted for next time and for the unwary. Be sure to get rid of any and all bubbles, regardless of how small as they will still be there after curing. And in my case, in a couple of windows, they left a small unfilled area on the exterior.
I think I could do better with a more precise means of applying the resin (perhaps a syringe through a needle blank). I was using a fine disposable brush. Also, because this was lower viscosity, it is important to make sure the window openings are level during the cure. Finally, to be absolutely sure, I cured these windows from both sides of the fuselage before removing the clear tape on the exterior.
I used a UV light normally used to cure fingernails makeup (gloss resin) on people who go out for that sort of thing. I got this on Amazon for a small amount of money.
In this photo, you can get a glimpse of the windows. What I am doing here is pre-installing the interior into one fuselage half. The fit is not perfect and I wanted to make sure it was properly installed on one side before gluing the fuselage halves together later.
As a side note, you'll notice that the turret opening has the shaft installed. This is a simple "T" shaft which is supposed to trap the mounting between the turret lower half and the "T" shaft , so that the turret can spin. I glued this into position and when I install the turret in the future, I will glue it into whatever position I need for my diorama.
Finally, I've done about 75% of the fuselage rescribing and riveting, leaving the tops and bottoms until after I fill in the seams.