I would hold off on judgements on blue wheaten and wheaten pullets and cockerels until 5-6 months at least.
A technique I used to make culling easier with my lines was to leg band and take pictures of blue wheaten/wheaten chicks at one week intervals. I found that over time in my lines certain plummage development patterns generally led to the best birds and I was able to cull much earlier. The patterns were very much line specific. If I added a new cockerel or pullet from outside, all bets were off for several generations until the new line stablized.
Michael