I would suggest talking to whoever is the head of the section that does strata management. Explain the complex projects you have coming up and that you are concerned that you want an experienced manager.
It is a common problem. Out OC is not ordinary in various ways and we had an excellent manager with a lot of experience but she moved to another part of the business. We had a run of less that wonderful managers but the latest one is much better. Nonetheless, having a few experienced people on the EC is essential too.