It kind of depends on what you are looking for. It sounds like it's improving compilation times while you develop so you can get errors messages from the compiler and so on faster which SBT incremental compilation should help with.

Are you guys currently using SBT? If so, is incremental compilation not working for some reason (or are you not aware of it?).

In terms of time, it would really depend on the size of the project and what is currently in place. It could be a couple of hours to a few days.

BTW my email is in my hn profile you want to discuss more privately.