I want to beef-up one of the M-4 Bushmasters I have. It currently has an EOTech 512 sitting on it. I want to add the EOTech 3X mag and a set of BUIS (back-up iron sights). The EOtech 3X will be the side flip type. One of my problems is that the forward handguard has no top rail to mount a front BUIS on it. Any recommendations on how I can attached a front BUIS on this weapon and what manufacture recommendations do you have for the rear and front BUIS?