as for stopping the oil moving back on hard acceloration i would have thought something like what L20b sumps have would be good. just a flat plate on a 45 degree angle coming out from sbout where the rear mounts are in the sump pictured above
think they just have gaps on the side to let oil back down

also interesting that the earlier A series sumps dont have that baffle in the main reservoir like that later ones. atleast im pretty sure the early ones didnt