The Krome 61 is only 16 lbs...your BK-9 weighs approx 21 lbs.

I'd say, in this case, the seemingly slight difference of 5 lbs is enough to make the Krome noticeably less stable.

Since the BK-9 is still quite light, do you need anything grippy under it to keep from slipping?

My demo PSR-S910, at 24 lbs, was pretty good, but it was just the right size (front to back) to be resting on all four rubber end sleeves on my double braced X-stand.

Ian