Skip the headed bar, and the standard washer.
If using a washer, it needs to be a plate washer stiff enough to transfer the anchor tension into the concrete, something like 2.5" x 2.5" x 5/16". Standard washers are too 'limp'. Now, the bottom nut will also need to be 'locked' in place. Staking HARD in 2-3 places works, and tack-welding it twice is best. Too much work/$$ for me.
Just put an "L" or "J" bend in your anchors. Done.