Prepared the HS-404 to fit on the HS front spar. Drawings made this easy. I checked the measures on the 1:1 drawing for accuracy before transposing the cut outs to the HS-404. Used #30 drill for the corner and the band saw to rough cut. Various files and metal sand paper was used to dull all edges and corners. Right HS-404 is just a mirror image of the Left HS-404, hence the left can be used as template if positioned bac to back.
Turned out pretty decent. The time the band saw worked fine (thin material), I learnt my lesson from earlier and will only use the band saw for rough cuts from now on.