Should I use spring webflux in a REST microservice

I am thinking of using Spring WebFlux in a set of micro-services that are used by a single mobile app. We expect number of active users of this app to grow to around 50 Million users. We also expect bursts and micro-bursts in traffic.

These micro-services will essentially wrap a set of REST API's provided by our base legacy systems in addition to adding certain amount of business logic. API calls to legacy systems are quite slow and I expect threads to be blocked in these calls most of the time.

To have a better throughput, I am thinking of using Spring WebFlux instead of Spring MVC directly. My hope is that this will allow us to run the service with lesser number of threads, there by making it more responsive to changing loads. Also I hope the overall latency profile of API calls to become better (less variation).

Does this sound like a good idea? Or should I just stick with sprint MVC?