It's not required to have a return edge. I'm actually getting rid of mine so I can have that tiny bit of extra room to pull my thighs up a tad. Matter of fact, none of the guys I trooped with this last weekend had thigh return edges either.
Looking great! You might want to consider going with a hardhat liner that has the built in sweatband though. There's a bit of cushion there and helps reduce any wobble.
For gluing elastic straight to plastic, you can put a patch of spare ABS on top and clamp in place. You'll see ukswrath always do this in his tutorial photos. That circumference looks right. I used my pipe for my thermal detonator.
Nice! Well if you get stationed at Fort Drum after receiving your commission, you'll be in my garrison. Albeit, on the complete opposite side of the state.
A third coat will finish this up. I wouldn't worry too much about squaring off that top part but with your attention to detail, you'll be able to no problem.
Just make sure you give it plenty of time for the acetone to fully evaporate and the abs to harden. If you rush it, it'll feel spongy and you'll have a bunch of pinholes.
Awesome work! Yeah, I had about an hour window last night to do my box so I just winged it. Looking forward to see your trooping photos. Mine is next Saturday so I'm in just as a mad dash as you are to get things dialed in.