I've managed to get it down to about 30fpm (it used to be much faster) recently. It's one of my biggest issues I'm trying to work on with diving and I know it but haven't been able to slow it any further - I usually do my SS around 18-20 feet because once I hit 15 feet I may as well be on the surface. I generally have to do my SS while finning gently down just to keep it in the right range. This is the case regardless of how much air is left in the tank - could be 500 psi, could be 1600 psi, it still happens - no air in the BC at all, not holding my breath, etc. I am just super floaty in shallow water (I have to fin down to about 20 feet after splashing).
Below 20 feet I have no issues hovering at whatever depth, its just the shallow depths I really struggle with. Because of this, if I do any diving deeper than 80 feet I add a SS around 40 feet for 3 or so minutes followed by my 18 foot or so SS for 3-5 minutes.