If you are still experimenting .... for my RLS, it turned out that B3=Niacin is very helpful, even after onset; And also sufficient iron.
When I take iron in the morning and B3 whenever (morning/day), I don't get RLS.
And important: if you do experiment, I found that only "real" flush-causing B3 works; Not niacinamide/nicotineamide, which apparently has some of the (many) benefits of niacin, though no RLS relief (or flushing). And especially not inositol-hexanicotinate, which I have not found a single reference describing any useful property of (but still gets sold as B3).
When I take iron in the morning and B3 whenever (morning/day), I don't get RLS.
And important: if you do experiment, I found that only "real" flush-causing B3 works; Not niacinamide/nicotineamide, which apparently has some of the (many) benefits of niacin, though no RLS relief (or flushing). And especially not inositol-hexanicotinate, which I have not found a single reference describing any useful property of (but still gets sold as B3).