Finest acronym/abbreviation for the word “template”

What would be the appropriate method to reduce the word “design template” to optimum of 3 signs for usage in hectic diagrams and schemes in (bio)chemical context?
From here and there I just discovered TPL and TML examples to be more or less suitable. Likewise, just T is typically utilized in the specific literature, however I discover it rather inappropriate as it might quickly be confused with “temperature”. So which one is appropriate?