I beat Ra Mu and some IF bosses in that way (and Andromeda Infinity eh....). When i fight against visibe Andromeda Infinity, i cannot beat she O_O. It's easy when i don't know, where she is than when i know, where she is O_O O_O.
No, for me, my full-synchro can only be activated if i can see the enemy's movement and predict the next movement, thus makes Rockman evade the attacks