Share 'Excalibur to Lunar ratio?'

Well I sadly haven't brought myself to put up the money for a lunar yet but I have several Excalibur lamps that in recent years have become cloudy. I would rather refill them with Mathmos lava and fluid. So my question is how close is a lunar bottle to an Excalibur? Smaller or larger? Iike always I appreciate your shared knowledge and hope you all are doing well and staying safe! Thanks -ash