plumbing questions

I'm trying to figure out how to get more flow out of my return lines from my sump. I have a 1.5" line running from the pump which is split into two 1" lines to 1" bulkheads and then it gets weird. I'm using the bulkheads and return lines that the original owner had in the overflow box. For some reason the return lines are adapted down to 1/2" right away and then out bulkheads to 1/2 loc line. What I'm thinking is that the reduced line size is increasing head loss and the flow is suffering because of this. Would changing it to straight 1" PVC up to the bulkhead for the lock line increase the flow enough to justify the cost of the materials?

Thanks finally someone with an opinion. I'm thinking the same thing about cost vs increase. a Power head or two will be added in the future once more funds can be budgeted.