A couple of modifications to the plans. The L angle that originally secured the firewall base to the cabin floor was thin, with little depth and did not fully transfer the forces from the lower engine mounts to the lower longerons and forward fuselage. I had a thicker piece of aluminium bent by Alclad to the original specifications with a longer lonwer flange to catch the full engine mount bolt holes and other elements like the brace securing the nosewheel strut to the fuselage.
Also added brackets to the forward fuselage L angle arrangement to strengthen the structure and because of the lack of direct connection between the L angles in image 3 and the upper longerons.