Modals in passive voice

I see there are 2 ways to form passive voice sentences with modals 1) Conujugation of a modal plus a present passive infinitive 2) Conjugation of sich lassen and a present active infinitive #1 can become very awkward, especially in the future perfect with a triple infintive structure, so I lean towards the "sich lassen" approach. Which is more prefential in written and spoken German? Scott