When he powers up to 100%, Omega Seventy-Five shows bigger muscles on his arms, his head-pieces seemingly grow, as well as his cape. He is not shown to be able to sustain power between 10% and 100%.
He also first achieved his Ultra Rage version of the form during his final fight against the 4 gods. He is 5x stronger in this form, and is slowly dying and losing energy. Technically, his 500% form is stronger than his God form if we're going by transformations alone, unless we count the God version of Ultra Rage.