I have stake my 120 coins, and after one day, I got around 1 Solaris. Personally, this staking rewards rate is good because I know that there are lots of competitive stakers in the Solaris network fight each other to find blocks.
So you got around 5 stakes rewards in 1 day from 120 coins??, If so I wouldn't expect to get that many each day on average from my experience. I've had a day where with the 320ish coins I'm staking have given me 10 staking rewards in a day, I've also had a day (Yesterday) where I only had 2 staking rewards. I'd say I average around 4 rewards a day with 320ish coins.