Don't print on the plan,you can have best surface finish on vertical,and don't forget raft ;D
Post processing consist to cover surfaces with plastic putty (vallejo) or wall putty, solidifying and sanding,when smoothed use a primer and acrylic paint, i suggest to use this color: Base plate: black or metal dark grey Katakana Chart boundary and "berserk" white
Katakana Chart inside red
if you want a nice touch,fill the kanji with epoxy biocomponent resin mixed with red food color,and when solifying,a last light pass to all surface with transparent epoxy resin.
Made on zbrush with a reference logo image,the Katakana Chart and his boundary is a merged composition of cube (a sort of challenge) "berserk" inscription is make on 3DBuilder(windows app)