In this first shot, you can see I used a flip-stop to enable repeatable cuts and I drew a line on the fence to make it easier judge to where I needed to cut after the initial shoulder.
This next shot is the view of the nibbling out of the waste. Again, I didn't find the time savings of installing the dado blade to be worth it. I'd rather cut the shoulders of the tenon with my Freud Fusion blade and so made a series of cuts, broke off the waste and pared with my 2 inch chisel.
Although I don't want to fill the splits in the legs with epoxy, you can see here that it may prove inevitable. When I go to glue the ends with the short stretchers, I will use the West System epoxy and make sure they are set to dry with the split upward. I'll also use some blue tape to keep any epoxy from coming out of the split. After the glue up, I'll reassess whether I need to fill the cracks. Most of what I'll be concerned with is the aesthetics. If I get too much epoxy visible in the crack, I will fill it completely.
If you are a follower of Marc Spagnuolo's The Woodwhisperer, you'll be familiar with this process known as relative dimensioning.
Benchcrafted kit. Therefore, these joints were slightly more loose than a "slip fit".
After the first assembly, I checked for square and found I needed to slightly move the position of the tenons that let the top sit on the base by about 1/16 of an inch. To do this, I had to get on the bench and lift each end out of the mortises and carefully slide each long stretcher from the legs, all the while trying to avoid letting anything crash to the floor.
After seeing the piece as a whole, it seemed to me to be beefy enough to not need a fifth leg. Luckily, there is the The Sagulator. I entered the dimensions of the bench with 200lbs of dead weight in the center. Even with that, the bench should only deflect by .003" and the threshold on The Sagulator is .020", so I'm well within engineering tolerances.