My experience with DIY hood risers back in 2006-08 was that it would help vent a ton of heat from the engine bay while in city driving, trails, and at idle preventing heat soak. However, at highway speeds the windshield area is a high pressure zone so air would flow back into the bay and consequently flow less air through the radiator. I also installed a pusher fan on the radiator which helped a lot at lower speeds and didn't seem to hurt flow at highway speeds. YMMV.
I'd consider temporarily moving the large lights in front of your grill and see if you get a measurable drop in temps. Also making sure the radiator support foam seals are in good condition and not letting air escape around the radiator rather than being forced to flow thru it.