Такой бандурине лучше бы ТВД подошли. Поршневые двигатели кажутся маловатыми. И не проще ли было сделать сзади только одну пулемётную установку, но с широким радиусом стрельбы - чтобы стрелку не приходилось бы скакать от пулемёта к пулемёту, учитывая то, что в хвосте довольно тесно.
Very cool looking, but I think I see a few potential problems with the design: the two huge rudders and the high-up placement of the engines seem like they would be pretty big obstructions for the dorsal and tail gunners. Also, don't pusher propellers deliver inferior performance vs. puller propellers? Also, this is just a question, but why are the engines located so high above the wings? Since they're not jets, they wouldn't deliver the Coanda effect, so what's the purpose of them being located there? Very nice design, I love how intricately detailed your drawings are.
I think that attack from back is more likely than the side. Furthermore, if the arc of tail gunner's fire were covered by rudder (or engines), then target will be eliminated by dorsal turret, and vice versa. Accommodation engines highly motivated by a desire to raise the propeller to prevent their contact with the ground during landing, becouse the wing is locate very low.