Advice size beams

I am planning to make a Kossel but can't decide which beams to use.the it's going to be 1 meter high and triangle beams 305 mm.

For the pillars I want to use 2020 beams so i can use easily the Cerberus carriage and Graber v rollers. And for the base frame 2040 beams.

Would it be rigid enough?