XL 2016 Afficher plusieurs formulaires utilisateur les uns après les autres

Sub Ouvrir_UserForms()
Dim usf, n, t
usf = Array(UserForm1, UserForm2, UserForm3, UserForm4, UserForm5, UserForm6, UserForm7, UserForm8, UserForm9, UserForm10 _
    , UserForm11, UserForm12, UserForm13, UserForm14, UserForm15, UserForm16, UserForm17, UserForm18, UserForm19, UserForm20 _
    , UserForm21, UserForm22, UserForm23, UserForm24, UserForm25, UserForm26, UserForm27, UserForm28, UserForm29, UserForm30)
For n = 0 To UBound(usf)
    t = Timer + 30
    usf(n).Show 0 'non modal
    While Timer < t And t < 86400: DoEvents: Wend 'attente
    Unload usf(n)
Next
End Sub