IIRC, you only need the sleeve for the older mags. I think Hotbeam still has an ad for these in B/S/T which should have the details or just search for 'hotlips'. Also, the Maglight diameters have been posted before.
I don't have a V2 but I was thinking that most flashlights are larger internal diameter than OAD(Ontario (Kalifornia) Aluminum D or C-size AKA maglight). If it is smaller than you might try a cut up aluminum can as shim material.
I think you need to go into the tail cap slightly with 3Cs in a 2D so you may need to change the spring to a smaller diameter. I found an assortment at Home Depot that had one that worked.