Which male male joining ring for sigma 150 and reverse 50mm Nikkor (1 Viewer)

Looking to add a reverse 50mm Nikkor Lens to the end of my Sigma 150mm macro to do some super macro work. DWhat dimensions required for the male/male joining ring, as far as I know the nikkor 50m needs a 52mm diameter, is the sigma the same or larger?? Ie; do I need a 52-52 ring?

Anyone using this combo would be interested in hearing how you find it...

Sigma filter thread is 72mm I think. The Nikon will depend which 50mm.

Bill