Can't wait to try out this ship. We're almost past the barrier and then I'll make a few of these, hehehe.

It's been a while since I built this, but I remember it being kind of like drawing circles in Minecraft. On one axis, alternate Edges in a series from larger to smaller in the arc you want on that axis. Make a duplicate copy for reference. For the second axis, shift and resize the edges in a similar manner, adding the corner pieces to smooth the surface.
Due to the inability to actually modify placed blocks, this involves constantly placing temporary blocks to have surfaces to snap and scale blocks against. Also, twisted corners weren't in the game when I built this and should provide you some more freedom when smoothing awkward curves. Also, you can get more precise scale steps and grid sizes by manually entering values.

I've been working on my own version of the Shadow Cruiser and was wondering how you got the curved spikes so good?

your shadow ships are unbeatable, i love it

Great work. Thank you very much for building and uploading this.