Your part document contains 10 text boxes. You may change both text size and value in the given TextBox object if redefine its FormattedText property. See also this discussion.
Private Sub EditTextBox()
Dim oDoc As PartDocument
Set oDoc = ThisApplication.ActiveDocument
Dim oDef As PartComponentDefinition
Set oDef = oDoc.ComponentDefinition
Dim oSketch As PlanarSketch
Set oSketch = oDef.Sketches.Item("Moule")
oSketch.Edit
Dim oTextBoxes As TextBoxes
Set oTextBoxes = oSketch.TextBoxes
'reference to the 2nd text box (letter B)
Dim oTextBox As TextBox
Set oTextBox = oTextBoxes.Item(2)
'current text height
Dim TextHeight As Double
TextHeight = oTextBox.FittedTextHeight
'new text value
Dim St As String
St = "BBBBB"
'change formatted text
oTextBox.FormattedText = "<StyleOverride FontSize='" & CStr(TextHeight) & "'>" & St & "</StyleOverride>"
oSketch.ExitEdit
oDoc.Update
Beep
End Sub
You should be able to control FormattedText property from iLogic rule.
Cheers,
Vladimir Ananyev
Developer Technical Services
Autodesk Developer Network