It's up to the underlying protocol to determine when the read is "finished". For a Stream it's no difference between 1x30 bytes compared to 2x15 bytes. The 15th byte of the first 15 bytes should be followed by an END byte of some sort. It's in the application layer.
No it doesn't work in 64-bit, but in any case. You only add Franson.BlueTools.dll to Visual Studio. BlueTools.dll should not be added as it contains the core whereas Franson.BlueTools.dll is merely a wrapper.