Putting in the drawer dividers is a critical step. Because the drawers will be accessible from both sides of the bench, it's critical that the drawer openings front and back for each drawer are identical. If one is smaller than the other the "through drawer" will stick in one of the two directions.
Because the drawer divider locations were so critical I put them in with pocket hole screws. While this was a significant departure from the traditional joinery in the rest of the bench, it, like the rest of the joinery, is reversible. The spacer blocks insured that their spacing, front AND back, were the same for each drawer size. Note also that the spacer blocks, because they were the same thickness as the stiles, also prevented the drawer guides from rotating in the opening.
Now that the drawer openings are defined I can start start on the drawers. They're going to be another challenge because in addition to fitting flush in the openings, they also have to fit flush on the "back" as well and that means that their LENGTH will also be critical.
If I go with through dovetails or box joints this will be easy since it'll be a direct measurement thing. The length of the sides will be easy to hold in the opening and scribe where to cut them to length - no measuring or calculations to make. The "fronts" can be done similarly - hold them up to the opening, rip to the scribed height, hold the ripped piece to the opening, scribe the width and cross cut to the scribe line - again, no measuring or calculating.
But if I go with half blind dovetails things get a little more complicated. I'd need to account for the distance between the ends of the tails on the sides and the front of the drawer face. Here's why.
OK - so maybe through dovetails. But that'd mean the ends of the sides' tails will be exposed on the front of the drawer. The drawer sides are going to be poplar and its end grain takes finishes in a very unpredictable way, often bringing out the green. Looks like half blinds are going to be the way to go. Will take some test cuts to get the fit right and some careful measuring - something I try to avoid.