For sight reading, I'm used to the fixed-do. It's hard for me to use movable-do, that is seeing G in G major but pronouncing it as "do". I think it's not quite easy to transform them just in time. But the fixed-do, really, is not friendly to the melody.
I'm not quite sure if it's right to use fixed-do when be in sight reading. Or should I pay attention to the tune itself but not what name it is?