I've tried blocks of 50 and blocks of 5.  I'm currently using splitsize = 5 and combinelimit = 5 .  These are set in the clam.conf file.  After watching my staking info in the debug log, and now tracking it for a bit, I'm finding that looking at one days data is not the way to go.  And at your number of clams, I would think you'll need to look at, at least 2-3 weeks data to get an idea how your doing.  One day you might get 2-3 stakes and the next few days get nothing, and think something is wrong (at least I did).

   Also an interesting point.  I usually end up staking when the network weight is on the high side.  I would expect my staking to go up as the weight decreases but thats not the case.   

   I'm doing this more to help the network, then to try to beat Just-dice.  As long as I'm "somewhat" close I'm happy.