This is ok if you have a few bars and not a whole song.
In biab it's easy no upper lower case, and you can type chord K4 to copy last 4 bars, K8 last 8....
Type Chords directly in Master track with autocomplete option, see Google Auto Complete.
Maybe have different chord entry options, like the L/R cursor keys move to next beat you just type chord hit cursor x4 (or Tab) for next bar, x2 for half bar, x1 next beat, Tab <> bar forward bar back, R4 repeat last 4 bars, R2, R8, R16....




