After finally spending some more time with my He6se, basX, and A90 I can conclude I am pretty disappointed in the He6se with both amps. I have done tests with my siblings and cousins, all with no prior experience with high end audio gear and a pretty strong consensus, the he6se hurts their ears but the instruments are very clear. When used with the BasX the consensus was it was better that it didn't hurt their ear but they ALL thought the HD660S was the more expensive headphone and sounded the best. I'll admit that the HD660s has the soundstage that I wish the Hifiman had, the vocalist wasn't in your head but at a good enough distance where the clarity was still extremely good, and best of all the treble wasn't uncomfortable. With the hifimans I can enjoy the details the HD660s can't offer but only for a couple of songs before my ears need a rest. After nearly a month with both headphones I have to say I too prefer the HD660s quite a lot more.
My only conclusion on the possibly to why the Hifimans aren't as impressive to me is likely due to the amps I am using the A90, and the BasX. Just like another user who has both amps mentioned they both weren't impressive with the He6se, I too have to agree. I feel pretty desperate to give the He6se a better chance with a different amp like the jotunheim but I fear the I may go too far down the rabbit hole and my wallet isn't going to have any of it. So just my amateur 2c on the He6sev2, avoid the topping A90 and BasX amps.
You could try it on the V281. It sounds great with it.