There isn't especially much to optimise equation wise given there's basically only two clearly beneficial scenarios:
- 0 bar pressure, 1 mb/t flow for every 100 HU/t
- 221 bar pressure, 1 mb/t flow for every 200 HU/t
Everything else is just interpolations between those (or above, given that the second is 374C yet the maximum is 500C) which use more annoying to produce numbers without any benefits over either of them. Steam is just like that at the moment, one day it will better scale to allow heat to be more analogue than it is now.
I hope so.