Thank you guys for advice.
I actually changed my plan. I am thinking about not using risers, so I will just plug in my gtx 770 and two gtx 1050s directly into my motherboard.
My only concern now is that I cannot supply gtx 1050 with power from my psu 6/8 pin connectors. Will my motherboard be able to provide the x2 75W (150W total) via the x16 pcie slots for my two gtx 1050s ?