D-Bus API based peripheral need guidance on setting Advertising_Interval_Min and Advertising_Interval_Max

I have a BLE peripheral running on top of Raspbian Buster, Kernel version
4.19 and BlueZ v 5.50.  I need to set the advertising interval from the
default 1.2 seconds to a much more aggressive setting say 200mS.  Can
someone please give my guidance on the best way to achieve this.   The only
way I can find to do this is to completely setup my advertising packet with
the HCI tool.  I have to be missing something. Is there a way to simply
change the default advertising interval?  

Thanks 
JR