As my harp uses loop end strings, I've never bothered removing the chord bars, and re-strung one at a time - less trouble tuning.
I pull the loop end of the new string through with the old one...
As regards 'choking', I often do a waltx-time oom-ching-ching effect by, for example, pressing F and C together on 'oom' to play only C's, and releasing the F bar for the 'chings'.
My harp is at least 30 years old, of German origin, black with a red rose motif. It only has 12 bars, and I've re-arranged them into the same order as accordion left-hand buttons... much more logical!