I should have been more clear. I posted the previous picture to show what box I am working on. It is already stuck to a piece of wood. I did this to shape the parts so they flow together.
Now, I could solder tabs on the top side to keep them in position while in inlet the box. Releasing the glue only requires a heat gun.
OR, I could inlet each piece separately.
Which plan is most likely to give the best result?