I'm a bit late to this discussion but...

Here's an excerpt from a private email sent about my Seller's
multi-year wood-wrestling project.

"
I'd emphasize not using the material I did. Truer, easier material
would be better. Jointing the faces for the slab hasn't been fun. I
had considered using alder, ash, or beech milled [and S2S] to 1-3/4"x2-1/2" but
decided against it in an impulsive move. For someone looking for a
quicker project, choosing a more suitable stock is a good idea.
"
That's the polite way of stating it. I had one board, intended for a
stretcher that must have twisted 20-30 deg. While the SPF borg
not-at-all dry lumber is a lot easier to work than doug fir, it's been
a giant pain. If you have access to a fully-stocked shop for a weekend
(jointer, planer, etc.) then you can get it all done, glued up and
only have to worry about some of the specific joinery.

However, my lams came out decently. I trimmed them to length (total ~8
in. of waste from both sides) and the ends were all solid, most
breaking through the wood just a Sellers demonstrated. My aprons did
twist a bit but nothing that a few strategically placed fasteners
won't overcome. Not a total loss, although...

The worst part is that as I'm getting everything ready to assemble I
realized I'm not even going to be in love with the bench. The aprons
mean you can't sit at it with your legs under the top and you'll rub
your knees on it while standing in certain positions. Plus installing
the vise is a far more challenging enterprise than on an open-face
bench. The only bonus is that you get a deadman where ever need one.

Next time (maybe soon) I'll be going with a more common trestle. A
couple extra M&Ts looks pretty appealing compared to 10+ joints for
the aprons. I'll probably go with ash although it's crept up in price
around here (guitar builders) and with all this recent discussion of
beech it's still in the cards as well.