I grabbed my tape and went nd measured where my brace is mounted in my 16x54 Willie. With my rowers seat on the middle peg the back edge of the foot of the brace is 20 inchesfrom the front edge of the rowers seat. The brace is set back about 1/2 inche from where it was when I got the boat. I actually broke 2 of the mounting bolts that hold in the brace and had to remount it. The angled art of the brace mount goes towards the rear of the boat.
Use stainless steel lag style bolt when bolting in the brace. Snug them down tight, But not too tight. If you tighten them too much the heads can shear off. Believe me I know.