Nothing definitive, but this is what I came up with based on 2018:
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To be in corral E (the last POT submitted corral), you would need a 10 mile time between 1:56:36 - 1:58:52 based on the conversion used. You would need a 2:36:06 - 2:38:17 HM based on the conversion used for a 5:30 M. I believe runDisney is on the faster side of the conversions necessary (so the 1:56:36 10 mile and 2:36:06 HM) to hit that 5:30 Marathon conversion.
Also, I played around with the registration. I was able to confirm, that if you choose a non-POT estimated finish (Over 5:30 or Over 2:45), then you are asked for an anticipated finish from a drop-down menu choice. Those three choices are very likely going to represent the last three corrals. If you choose the 1st of those choices, you will be in the 1st non-POT corral (Corral F as seen above). If you choose the 3rd of those choices (like 3:16-3:30), you will be in the last corral overall (Corral H as seen above).
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