I use a cf15 so the results may vary but I will just give an example of what I do for my neipa. I dry hop in my conical, before that I soft crash and dump yeast. I dry hop at 55f and rouse the hops via co2 in the bottom port. Come time to keg I cold crash for 2 days, the past 2 neipas I've done I have left the dry hops in so my only dump was of yeast before dryhopping. I set my racking arm around 10 - 11 o'clock position and I purge the transfer line a couple times until the racking arm clears of hop debris. I use and inline filter so I don't clog any poppets. I have filled 3 kegs completely doing it this way the past 2 times, I fill my kegs by weight. I also fill my cf15 to the rim when I brew a neipa because there will be losses no matter how you go about it. Yes we try to limit them but its inevitable, even with the dry hop keg, if you think about it, the amount of space taken up by the hop spider with hops in it is also a loss to final volume, though probably minimal. And I will add I think that is a great idea and a sound process, not knocking it at all, just putting another option out there that I have found success with.
Cheers!