Is the horizontal what you need to irrigate? Is there any elevation drop there? If you just put your IBCs at the highest point, you will not need a pump with 275x4 gallons of pressure.

I would recommend putting the IBCs at the barn to top feed them straight from the gutter, otherwise you will need a pump to go from the ground to the ibc tote top. Bonus points if you put them on the north side to block the sun. More points if you both paint them black and wrap them to eliminate algae growth. Both are needed, I see systems with one or the other and the sun still leaks in.