Electroforming 925 Silver

Does anyone have any consistent success in electroforming 925 silver
or will 999 only work. Which proprietary chemicals are the best
generally. I am using 10-12asf (same as for plating) and copper
forming seems to work broadly ok but I am having so much trouble
with silver. Not sure if its just me not manageing the electrolyte
properly or if I am being unrealistic in trying to get silver up to
1mm.

Any small scale (I know big commercial outfits can do it with their
own ‘secret’ electrolytes) operation have any good successes with
purchased electrolytes ?

thanks
Keith Elliott