I've got two of the fins currently glued in, as well as the motor mount. It's actually beginning to look much more like a rocket than just a bunch of parts.
Unfortunately, I made two stupid mistakes in building. The first was accidentally aligning the motor retention rod with one of the fin slots; so I'll have to cut the fin tab to make it fit.
The other was to not notice a near-break in the shock cord I used (formerly the shock cord of the Nike-Apache), which I repaired with kevlar and a little bit of epoxy.