Can someone please tell me how much SYS would I earn per day with 3 x R9 290 (probably arround 800 Kh/s per card) on this multipool? I can't find the way to calculate this myself.
Simplest way to estimate your earnings (and check if the pool is paying honestly!)
is to find the average network hash rate (each pool displays this, so just read it a couple times with a few hours in between)
and divide your hash rate by this network average hash rate. The answer is very small, typically in the order of a thousandth to a millionth.
Then multiply this number with the coin supply per day (the block reward times the nr of blocks per day)
Note: the nr of blocks per day is the nr of seconds per day divided by the avg block time, typically 60 sec, so the answer is the nr of minutes per day = 60 * 24. Multiply with block reward (128 coins) and that is the coin supply per day: 184,320 coins (shown in OP).
The block explorer tells me that the current network hash rate is 35Gh/s so one card at 800kh/s is 1/43750 of total hash rate.
So 3 cards should make: 184,320 x 3x 1/43750 = 12.64 coins per day in theory when network remains at 35 Gh/s.
So, if you are solo-ing, you should find 1 block every 10 days.
Hope this helps!