Sent 0.06
BTC and got a match, too bad it was just a demo play as it was my first deposit and so I did not get the 0.15
BTC 
Well, there is nothing magical in 0.06
BTC ticket amount.
In your demo play case:
f556c00e8f217ce95e19c0d6637b23ad998e376b63bd1ee26c576a96209a7d0a - txid
0954833d9c07710d66cd3af54d1d3c867c67bd773c200ee1b5e3daab8db61b64 - Merkle root
Optimal (max profit) amount was 0.54
BTC -> 5 matches, 0.75
BTC payout, 0.21
BTC profit.
For the next ticket maximum ROI was for 0.11
BTC amount -> 3 matches, 0.45
BTC payout, 0.34
BTC profit.
PS: free 0.01
BTC ticket: txid=
974b0d8eb737d80397299bc84225d756550e7b10d1425fad8137703113fab6db