I'm trying to run solo via the
http://solo.ckpool.org/ but however just a tiny fraction of shares are accepted. Is it possible to increase prevetively the minimum difficultiy form my (miner) side? I see the +diff option was named above. However I can't fid any relevant information regarding this option. How can I use it with my USER(i.e. BTC address) parameter?
You're posting in the support thread for the ckpool software. The solo ckpool thread is here:
https://bitcointalk.org/index.php?topic=763510.620However the quick answer is with solo mining it doesn't matter how many shares you get accepted since you don't get paid for shares at all and you only get a reward if you solve a block. Don't worry about what diff it's using since it's just an indirect marker of how hard you're mining.