What I was saying there is that DefaultTrust effectively puts 100 people on your trust list (quasi-directly, I mean; I'm not talking about what the final number would be after accounting for depth). I haven't pondered this deeply (maybe there's an off-by-one error I'm making about where in the recursion the 100 inclusions actually happen), but, my point was that accomplishing a similar level of "coverage" (with a completely-custom trust list) is going to be unrealistic for most users.
My gut feeling tells me it doesn't really matter: many users include the same users, so there's an overlap. But more importantly: the users on my Trust list (at Depth 0) add their Trust list to my Depth 1. Based on
my years old data, the 23 users on my Trust list give me 183 users on Depth 1. That's already more than DT1.