I have ~ 6000 sft 21x15x18 room and I'm buying new tritoncinema
I'm planning on using Triton two, super center xl and supersat 60 on a stand for satellites in 5.0 or 5.1 setting
when setting up the speakers with the av the super center xl and supersat 60 should be set as small?
does the Yamaha advantage RX1030 has enough muscle to push this system?
do you think I will need additional sub?

Yes, set to small. Crossovers as per the manual suggestions. You won't need an additional subwoofer. Sorry, not familiar with the Yamaha but I'm sure it would be fine.