This is certainly the easiest way to get a working implementation, yes. There is an existing (but I don't think maintained) FUSE port of HAMMER and it would not

This is certainly the easiest way to get a working implementation, yes. There is an existing (but I don't think maintained) FUSE port of HAMMER and it would not be a huge amount of work to have HAMMER2 FUSE support I don't think. I am interested in a kernel port of HAMMER/HAMMER2 because I think this is likely to give the best performance in the long run.