This is the first model, with the large gap filled. This is just the rough Aves putty. Since this picture, I've sanded it smooth. I found that on the other two models, shaving down the location pins inside allowed me to eliminate this gap completely.
Three Trencher models complete ready for primer. I gave them a first coat of primer right after taking this picture. It's difficult to get the whole model at once, so I'll finish up the topsides tomorrow (or when I have the time).