Tips, Tricks and Hints for aligning hull before gluing

OK, I've got the Coho (stitch and glue kit, not a stripper) hull all stitched together, with temporary formers wired in. Instructions say to turn it upside down so that the spacers (fastened on top of the temporary formers) sit on a level surface, "fair the hull", and glue away.

I've got the hull planks pretty well aligned during the wiring process - instructions say to align the bow-side plank seams (a butt joint) as each new plank is wired in. I can't be off more than 1/16" in the seams, although due to minor discrepancies when gluing the bow/mid/stern plank pieces together, there is one section along the bow hull seam where there's about 1/8" to 1/4" difference.

Aside from the problems in finding a level surface (instructions call for shimming up sawhorses until "eyeball" level), does anyone have any suggestions about fairing and aligning the hull before gluing? Any tricks with chalk lines, plum bobs, etc?

TIA

Ed