It's your choice, of course, but I still think the PO valve would be the best answer for your situation. Pressure is what makes hydraulics work, it's what they are designed to work around. Your system now generates pressure to move the cylinders, opened or closed. It's the lack of captured pressure in the cylinders when the pump is stopped that allows your hood to creep open. Putting a PO check valve in the hydraulic line between the cylinder and the spool valve/pump will lock the cylinders in the closed position with a negligible amount of pressure. Since the spool valve/pump will be idle when the hood is locked closed there will be no extra load placed on them.
Remember, hydraulic oil is sometimes called "liquid steel" with a system like I've described the PO valve is nothing more than a latch.