That is where I was heading... Why do you guys need a 210 petty? I find it the most redundant knife (size-wise) out there. I think anything over 150 is where a gyuto comes into play or a short suji (if you do trimming).
Wa handled petties (150mm that is) are fine but a handle has to be of a right size in relation to the blade and a hand of a user and I give a D-shape handle an edge over an octagonal. Your experience is probably due to the fact that petty handles on Japanese knives rarely matched to the knife (that has been my experience and I rehandled a few), so they are either too small or too big.