All the doohickey (bridge jack) does it stop the bridge from disappearing into the trem cavity once the tension from the strings is dropped.
This can be handy when intoning the guitar however I just undo the strap locks and de-tune that string.
So it is not really necessary as any change in tuning is still going to knock the other strings out of tune.
I made a bridge jack out of a dead 9V battery wrapped round with electrical tape and don't really use it !
FRs are just a total pain in the ass to work with. The are great once they are intoned and tuned and all however getting them to the point where they are usable is a real labor of love !!!
I have spent this weekend stripping down, trouble shooting and then re-setting up my Jackson. I have just about got it sorted out now but it has taken me maybe 6-8 hrs and I have done this before several times !!