Something I noticed with other sites that struggled to get people is cancelling freerolls due to lack of people made the person think the site would never run and they never came back. If you look at the now defunct Luckflop.eu,they where always 2 players off running and people got tired of showing up day after day in hopes it would run.
Maybe lower the payout in those cases and run them anyways as it does not take long for word of mouth to catch players interest in the site.

The one aspect you seem to have going is busy at hours where others are lagging,if that continues it should be good for the site.