I think it is important that there be a separate AI, and DI for an iniitio training. Yes you can get one GI 275 to do both but I think there is too much programming and display complexity. Personally I think 2 G5’s are far better than one GI275.
in any case I think you should make sure that you wire the GI 275/G5 to a separate power switch. This means you can turn off the glass for the foundation flying exercises (A&M, St & LvL, Turns, Climbs & Descents).