Place code in userform, module or class module

In the attached workbook is an attempt to enforce formatting to certain textbox entries in a multipage userform. The reason for this class module approach is that this is the groundwork to apply to a much larger application when sorted.

I have control of the formatting of the textboxes I require by way of choosing to set a array in the class module.

On multipage1 first and last textbox has no entry restriction - 2 and 3 are set to a date format "dd mm yyyy"

I wanted to add an exit event that requires the text length to be a minimum 10 digits

In the bottom right corner I have a test textbox that behaves as I wish it to by way of

Private Sub TextBox1_Exit(ByVal Cancel As MSForms.ReturnBoolean)
        With TextBox1
        If TextBox1.Text = "" Then Exit Sub
            If Len(TextBox1.Text) < 10 Then
                .Tag = ""
                .SelStart = 0
                .SelLength = Len(.Text)
                MsgBox "Please Enter Date in dd mm yyyy format"
            Cancel = True
            Else: Exit Sub
            End If
        End With
End Sub

I would like to have this format for all the textboxes declared in the array but it is failing me as to where to place or how to code it. I have tried replacing

TextBox1

with

NumericTextBox

as I have used elsewhere but to no avail. Any pointers appreciated