I am curious if anyone can help me. I would like to know if htere is any research as to whether two oil lamps of equal size and shape, one contains 5oz of oil and the other 8 oz. The wicks are the same, in fact they are both floating wicks. All other related information is the same. Would one of the lamps provide more light, heat osr a better flame?

I wouldn't think so. The 8 OZ lamp would simply burn for longer. A lamp could be made to burn brighter by raising the wick to that more of it is burning.