Yes, apologies brahmist, not been on here much myself of late, but i'm sure the lack of response to your query was not a deliberate rebuff!
Anyway, Silkies, they are notoriously hard to sex as you have found! I used to keep Bantam beardless white Silkies, and generally speaking, found the cockerels to be larger, longer in the leg and bigger in their feet than their sisters of the same age. Wattle development was usually greater in them, and the Cockerels ' fly-away' crest streamers would begin to show in their more feminine, rounded Chick's crest.Males would also be finding their deeper adolescent voices at this stage, with attempts at crowing, whilst pullets will still be sounding like chicks.
You will find there are always exceptions to these guidelines, with smaller, slower developing males that appear to be pullets , usually birds that have had their development suppressed by bigger and more dominant brothers in the group. Once the obvious males are removed from the group, these slow starters often transform into cockerels within a week or two! On the other side of the coin, you sometimes find larger, quite masculine looking pullets in a brood, that surprise you by coming into lay!!
Of course in Pattern marked Silkies, like Partridge and even in some strains of golds, plumage colour and marking differences between the sexes will begin to show, with males beginning to show more uneven shades, with stronger and darker hues, whilst pullets will be of a more even shade, or showing softer more subtle colours. Males of some strains of Black Silky will show gold in their necks at this age, whilst their sisters wont, or at least they will have far lighter and less obvious 'brass' necks than their brothers.
I hope this helps, LC.