Glass filters is the best (?) choice for a good sensor, since the ageing is low and you can get them with good optical tolerances and little variation in transfer function.

But in this case, I would think glass filters are too expensive. And the OP has already noted several times his limited outlets for components. Colored plast film has big problems with ageing but is very cheap and can at least tell if the light is reddish or blueish even if there will be big problems with the precision - especially in relation to how our eyes auto-adapts and sees the color.