This morning before we started the PR3 moves which unlocked the IFO, I tried turning on a gentle boost in DHARD P, shown in the first screenshot:

  zpk([0.5+i*0.6245;0.5-i*0.6245],[0.34375+i*0.429344;0.34375-i*0.429344],1,"n")gain(4.00641)gain(0.639513)gain(0.82635)

This made a modest reduction in the RMS, which could be slightly better if the boost is made more aggresive. 

The noise at 1Hz is coherent with LSC MICH.