Bonkers
30 litres or so volume?
Not sure, just based around the original plans http://murphyblaster.com/files/MB1_Enclosure_Drawings.pdf
Probably closer to 20l. Which drivers?
Cad software says 10 litres.
IT doesn’t need much sanding, the cutter is a little blunt, the fluff just scrapes off, just easier to do it when its all glued up.
Looks a bit wobbly. Perhaps you should have inserted a couple of guide rods. 
Personally, I’d have dowelled it. 
That too. I think I might be getting early stage dementia, because I was wracking what passes for my brain for the correct term and it only came to me well after I’d posted .
We shall see next week when I actually glue it all together. 
I used small dowels to index and prevent slippage during the glue up of the lenco record players i built a few years ago. The 1 inch long ones are ideal for 18mm ply, linking 1 layer to the next .
(Sorry if that’s teaching you to suck eggs.)
Like I said above, the ply cutter I use, an up/down cut compression bit with 1 flute, hates drilling holes. It sets fire to things.
So to use dowels I’d need to use a drill, which would mean tool swaps and resetting z height every layer which would have been too much like hard work.
If they won’t locate from the Corian plates front and back, I’ll set up a jig to drill holes for dowels.
Methinks you will end up doing this.
Oh probably, but I’d decided the jig method was the fastest.
I reckon I could also machine some clamps to hold the sides, or machine the top and bottom piece to take a beam that runs up the inner walls.
Or a big frame that goes around the outside with some allthread to make the clamp.
No end of options. I’ll probably just glue a couple of layers at a time then sand the sand the fuck out of it. If it’s shit I’ll get annoyed throw it in the wood stove and buy some Corian.