Hello, as @theissen said, for yafu you need a lot of cores and more testing time. Some tasks can take more than 24 hours to complete. For me NFS@home and Number Fields worked better than yafu. I "mined" for almost a week, but came back to only NFS. Now making a 20$/month profit. I still have 3-4 weeks to go before the MAG caps, hope to pass 100MAG.
About the sinc problem, sometimes I get that too. I usually wait few hours, or if I have to update urgent, I just restart the Server and it will sinc then.
Good luck and happy, rewarding "mining", crunching, BOINCing or however you like to call it :)
You are correct. After block was finished it showed up in a pool 2 in my Grcpool manager. OK so this is working :-) thank you!