The SST-20 does show a tint shift at an angle, more rosy straight above, clearly less red at 60 degrees. It is just a lot better than Cree leds but certainly not absent. Plus they show heavy tint shift with current changes, but that may not be a problem in this application

Optisolis leds hardly have tint shift at an angle and have pretty good output, can safely be driven at 700mA and make over 100 lumen per led.