TL;DRI will like you to synchronise belts speed
What ?Yellow : half speed as the red one
Red : half speed as the blue one
Blue : twice as red and four time of yellow.
Why ?Simply because the blue belts does not match the splitters logic by working 3 times faster than the yellow and 1 time and a half the red belt.
If it's done like my suggestion, we can efficiently use splitters as one blue feed 2 red who feed 2 yellow.