Is your feature request related to a problem? Please describe.

Allowing the difference of source blocks and flowing blocks will help balance the mechanic of melting in a crucible. Currently, any liquid used can provide full speed which can severely limit design choices.

Describe the solution you'd like
It would be best if we could set a recipe using the liquid level to assign a specific heating value:

Additional context
All previous iterations of Ex Nihilo used this feature and it's very useful in pack design.