i have a lower flow on my 125 right now and it just doesnt do a good job of skimming the display even with a gyrepushing the top water towards the weir.
It’s more important to get flow in the tank. With multiple pumps. I would leave the corner over flow the way they are. I would setup two return pumps.
One on each side. Or one big return that can handle
The pressure. The corner over flow on that 300 are perfect for that size tank.