Try using -f 256 on suprnova. -f 32 on hashharder seems to also smooth out the shares a bit.

Edit: Seems that hashharder might be having issues, even if shares show as accepted in ccminer. I would stick to suprnova for the time being, as the expected payouts with -f 256 are much higher, and the pool-reported hashrate is much more accurate (reflecting a more accurate sharerate).