Best Box for low bass FANE 18XB

I want to ask for help to select the most appropriate size hole in relation to efficiency for low 18XB FANE
Get the planes of the Rhino boxes I have recommended a lot but are very large from the point of view of space and ttransporte was looking for something similar but smaller smaller as RCF RCF PFR180SW ESW1018 or reflex or some other model or smaller scoops it and render it efficiently in open sites
I would like to know what would be the performance of these low in these two RCF boxes I mentioned before there will be no way of knowing that such conduct could FANE 18XB low in these acoustic boxes?

thousand Thanks