To answer your second question, you need to measure the diameter of each bullet with a micrometer - which I have not done. I have, however, shot both bullets in my 6mmBR and the Berger VLD is more accurate, at least beyond 300 yards. But at shorter ranges the Hornady 105 shoots very well. I use Varget with all my 6mmBR loads.
I have shot 105 amaxs, bergers vld and hybrid, and 107 smk's, the amaxs and vlds are equally acturate in my 6br with rl17 at 600yrds, at 700+ the vlds take the win, and the hybrids are even better. On another note the 105 hornady bthp match is the most accurate at 300yrds.