Update: I have tested my HCT at home twice now, the process was quite simple and I got samples within 20 minutes from first washing hands to putting all supplies away. I made up a ziploc bag with all needed supplies for next time so it will be even quicker, maybe 10 minutes total.
I went from 56% HCT to about 50% after my 5th therapeutic draw totaling 600 ml, and recently finished a 6th therapeutic draw of 660 ml, bringing me to 6/6 successes.
I drew another HCT test sample a few days after the last big draw and am now waiting for it to settle for measurement. I subtract 2% to account for the rounded tube bottom, and another 3-5% due to no centrifuge at home so the RBCs don't pack as tightly.
I expect this latest test to come in at 43-45%. Ferritin should still be fine based on previous measurement from some months back.